Let's try it. Oh yes, it's working, even I can hear myself. So it's very effective. First of all then an apology is just a spot of the type of the spelling mistake which some of you might be able to see in your head bone. Oh that's awful, if I was allowed to put a mark on the stratumnau university walls it would go over it now and change it. So sorry, my poor icing. But I've chosen the title. Ac mae'n meddwl yn y ffilm. Wrth gwrth i, mae'r ffwrdd yn 60 o'r ddefnyddio. Mae'n gwneud o'r cratio yma yn y Gyllid Gymraeg yw GSA, Pedia Trials, ymr�io gyllid yn ei gwneud. Roeddwn i yn ymddi'r sorg yw'r ffrindio oherwydd yw y chyrdwch yn Llyfrgell yn Helensbrough. Mae'n dwy o fynd y mae'r ffrindio yma yng Nghyrchaf yn 2014, a nid yn yw Peter. Roeddwn i yn ymddi'r ffrindio a'r ffrindio. Rwy'n gynch chi'n dweud yw'n ffoxid, yw'r cyfnod bwyd yn rhai i'r cyfnodd, ac wrth gwrs, rydyn ni'n ddynnu'n gwneud. Mae'n ddynnu i'r cyfnodd, ond byddwn yn gweithio. Mae'n cyfnodd. Rwy'n 60 o'ch rhan o hyn, o'r cyffredin ni'n gweithio. Rydyn ni'n gweithio i ddifartwch ar y cysylltu. Mae'n cyfrwyng chael eich ddîm, Mae'r bwysig yn ddim yn fwy o'r hollwg, yn ymlaen, ond, yma, yma ar dwy'r hollwg yn 2014. Mae'n meddwl i'r hollwg yn ymddi'r hollwg yn cystafol i'r hollwg, ac mae'n hollwg yn cystafol i'r hollwg, a mae'n hollwg yn bobl yn yno'r hollwg yn 2014. Mae wedi bod yn ei gwneud hynny o'r hollwg o'r hollwg yn y bwysig yn y hollwg. Mewn gweld addangol yw ddim yn siarad ac rydyn ni wedi'u defnyddio fyddio y byddwyr tîm oherwydd ei bod yn defnyddio'i gwybodau er mwynhaf fel eich llaw i yw'r wynau, i'r tynnu oedd ymlaen oedd y dalwyr i chi'n lle o'r ysgrifennu mawr newydd, a'r graddion gwlad yn 자edd ar y bydd y bwyr i'r ddiwedd i gwasgolau. Mae'r wath am y bydd hwn yn cael ei gwasgol a'r bydd, ac yn eu gweithio'r dyfu a'r hanes, yng ngzydwyd iawn yn ei mweithio gyfanol y Glaesgo ac oed i ddweud dwi'n Penol. Rwy'n credu, mae'n cael ei gwaith... Pan yn gweld y Lleidol, y Lleidol yma. Mae'r argwr plwyth крasol Lleidol iawn. Gweithio'n credu cy starvingu'u cwyl sydd na chael yr artist a llwyddo'n gwneud eich taithu yn wychydgol wrthyll drwng pa'r bruns a'r llwg hwnnw i'r rhanion o'r cyfrosol. Mae'n haf fach gennydd i'r tyniad hefyd. Mae'n cystro am gyframe hwnnw. ond mae weithio'r llweinach yn cyflaenol, sy'n hyffredig fel yllan â gyntaf oedd y Llywodraeth yn ein bod yn Maen pu ddweudio hynny i fatha ac y Llywodraeth yn siŵr yn gwych am y siŵr, ac mae hefyd yn achosigl. Yna Maen angen i gychwyn am yr heb o'r sgol yma, ac mae'n cadw ychwaneg i'r llyfr yn y Llywodraeth. Yn y math ymgylcheddol, ond y gallan maen yn Sefydlu'r Llywodraeth. Mae erdwyr ymnydd o'r holl gwerthu, ar y cyfan, The school is still very much part of the hill, and the community, a lot of students live there, have gone on to live there, and the community itself is full of people who have had an affinity, have been touched, I think, by Glasgow School of Art, none more so than, of course, last year, when so many people were awfully disrupted by and worse, really, by the fire of June 18. So there aren't many institutions that can stay in the space of four years. There have been two catastrophic fires, but, meanwhile, the school, as an entity and as an institution, has really continued to struggle and to be determined to deliver education and the student experience and also work with its community to make sure that, you know, that the broadening of the mind and that great generosity of spirit that comes through education is something that continues to be applied and extend and expand from that site. And it is very much what we expect of Glasgow School of Art. It is a world-known, a world-ranking institution, and it punches well above its weight. I'm just going to leave that on site for a moment, because it'll run, and it's important if folk don't know, because actually it was very important in the case of the first fire, just how the fire was stopped. And what I want to talk about tonight, because I was asked a year ago to do this lecture, so it was actually before the current fire of last year. That, by the way, the circular building is Henglaas Circus, as it was well known. It had various lives, but that's still there as the O2, which was also very badly damaged last year. But what I'd like to do is still talk a little bit about the project that happened, because it's very relevant, I think, what happened after 214, and the work that was done, because so much of that work at the time has now prepared us so much better for what has to happen this time. If we'd had the fire that we had last year, and it was the first fire the school had ever suffered, and that would be normal enough, we would really have been struggling, because so much was, we thought we knew about the building, but so much more was known about the building after the fire in 214, with the surface that were done, with all the digital scanning, with all the research that was done over those three or four years after the first fire. It's a hard thing to say there's a silver lining, because there really isn't, but I suppose if you were looking for anything, the fact that there's been so much time to really crawl over every inch of that building using the technology that's available to us now, means that we're much better placed to look at a reconstruction, not a restoration, as the first one was called, but a reconstruction. But that's quite an important slide there, just captured I guess, the building is probably a lot for you do know was built over two, over 12 years really, the money was only available at the start to build one half of the building, the east half of the building. So McIntosh had designed, well the brief was for a plain pragmatic building and it was quite puritan, that's what Francis Newberry wanted, he wanted the building to educe as he called it, I think a Latin phrase, he believed everybody has art and creativity within them, and it wasn't about educating which is something about telling you what you do, it was to solicit to induce the art from every person that has it. They have to work hard to attain that, but nevertheless this is what the McIntosh building was built to do, was to create a place where people would be able to explore and develop and build on their innate creativity. And what you see there is that when they did get around to building that second half, the second half with the library tower, by that time it was already outstripping demand, so they took the roof off the first half of the building on the east wing and then built up this fantastic long lantern light along the top, with more studios there on the east and there on the right, the professor studios and the library tower coming in and studio 58. So it's quite a schizophrenic building, the front fitted well with the tenemental form of Garnett Hill, it was quite industrial, those huge windows. The back was like a Scottish castle rendered using Portland cement that wrapped around and cloaked the building, so that was the so-called cheap elevation because it was brick and then hard. He was working to a really strict budget the whole time, which he utterly ignored, so it was meant to be £14,000 the entire competition, the first half got built for £14,000 which ended up being £21, but the time they'd finished the entire scheme it was £42 million, which is, sorry, not million, thousands, it's extraordinary what you could do in those days with £42,000, but it had in the end four different faces because it spanned his crane, it's undoubtedly his masterwork, I'm going to move it on from there. This was a fantastic photo opportunity for the building when the Newbury and the Foulas towers were demolished across the road, if anybody remembers, fairly brutalist buildings across the way, still much loved I think by a lot of the folk who graduated from them in design and silversmithing and whatever. But we had this opportunity to stand back across the road and take a kind of corrected verticals image of the Macindosh, and you just see there just so extraordinarily beautiful a building it was really, so as I say within the street itself, within Renfrew Street it actually fitted in pretty darn well, Creme Sanson, it always looked a bit pink and that slide makes it look a bit pink, but that's just how it weathered. But a plain building nonetheless, using the money it was being spent on the huge sheets of glass there or the big first floor studios, whenever people walked in for the first time if they didn't know the building at all, they'd always think if you lost the floor, particularly if the fire, they thought if we burned through in it, no, they were nine metre high studios capturing the northern light. It was very important at the time, obviously that in Scotland time it was on the very first buildings to non municipal buildings to use electricity, and it was drawing electricity off the cooperation on a very cheap rate, but it didn't want to be switched on at all if they could help it. So during the summer months they always ride on natural light, but of course in the evenings where a lot of the classes were run and where Macindosh himself would have gone if he'd been a student and he built it, so he wasn't a student there, then the evening classes were truly paid for so much of the schools really operating, they had to have the lights on, so it was really important though how much unadulterated northern pure light you could get into the building for painting purposes in particular. That's what we have left today of that front facade, so I will show you some other images, but just to keep going back and forth if you can keep with me. So what you've got there is a drawing of the building in the black and photographic imagery of applied to that so that we can start tracing how much storm we've lost in the second fire and the damage to it. So it doesn't look it from that slide, but certainly you can zoom right in and look at very hairline cracks on that and we're just doing a lot of the work just now to just quantify how much we have lost and how much more will be lost because without a doubt the windows which we lost, not the metalwork of them, but the timber frames saw these windows and the leaded ones in the middle. When the fire came out of those areas it very, very badly shattered the stone which I'll show you as it came through the building. So again just looking at that elevation, just a fabulously beautiful asymmetric, it looks symmetrical but obviously isn't, but the door and that central line of the double door in the middle is the central line of the entire building. But this is a lovely subtle juxtaposition of three bays, four bays, very neatly done, slight slimming of the windows on the right hand side. That was it after the first fire and at the time everyone thought dreadful, you can still see the fire appliances still on Renfrew Street there, but what we had effectively lost was the library which is, I'm sure you'll know in the tall windows there to the right of the slide, studio 58 above it and the bookstore above it or the furniture store above it. And the professor's studios and the main painting studios on this side were also very badly damaged, but a surprising amount had actually survived. So although it was catastrophic, we now look at that and think walk in the park. We could walk into the building, we could walk along those buildings and just see what the damage had been. Macindosh never did a great deal of drawing in his handover, but they are beautifully simple and very legible drawings and they cover surprising details. So it shows where, well for instance where sinks are going to be in each of the studios where the ventilation shafts run through the walls of the building. It was very early adopter, he was an early adopter rather than an innovator a lot of the time. Well he innovated, but he wasn't an inventor himself I think in many of his details, but he was fascinated with technology and making this building breathe I suppose with the height and with the scale. And also with the amount of people at that time in Glasgow would not have had indoor sanitary and there was things like TB in the air and a lot of fumes within the building itself because of the nature of the material. And the chemicals that they would have been using within it so it had to work, it had to really inhale and exhale as a building and he achieved that very very well. But you can see here he's got things like the lecture theatre at the top and then in this basement area he has the ornament and the sculpture studios down here. So he's within the clay of the building and the hill really and this is where he's putting his clay modelling people as well. So they're kind of coming out of the terrain I suppose, the heavy work of modelling. And on the top there you see cloak rooms, male and female. Again very unusual in its day and it was something that kind of came full circle in the last couple of years or in the last year when we were looking at putting the toilets back into the, let's go about, they'd been long since removed. Surprisingly no records of the loose, nobody photographed toilets, don't know why but everything else got photographed. Nobody has a slide or a shot or a video or anything, a selfie of themselves in the mactress toilets before they were ripped out in the, I don't know, probably successively over the last 50 years and renewed. But what he was doing at the time and this is Francis Newbury instructing this was putting in equal provision for male and female. It was very, of its time it was right out there, it wasn't just about getting men in to do sculpting, it was about women as well. And even in fine art it was one of the first institutions where women were allowed to do fine art and modelling and the drawback on that was always life modelling. So it was not always men but it would be female and male nude life models and there was a big taboo on that or an unspoken taboo throughout the country on that. And Glasgow was one of the very first to allow women to, I think, certainly with women and then laterally as well with male life models to work from the live model. So it was important that there was female and male toilets, interestingly enough what we were facing when we were putting the building back again within the last 12 months was the student body rising up and saying, no female and male toilets of course, we want gender neutral. So they didn't want to have the female and male which was a bit of a, well not on a problem but we think we're doing this authentically, we're doing this back to these plans and that was the female club room, that was the male club room and there was the one thing they were absolutely adamant about they did not want segregation of the sexes in the toilets. So it was an interesting revisiting of what Newbury was trying to do well meaningly at the time obviously. And these are the kind of students even then so you could see probably even then they were going to demand for something different. I always have to look at that slide and count the number of people and the ones who are actually just models and hopefully the guy top left obviously is definitely just a model. But there's a few others and I think there's four fake bits of people in there all together. But even then a rum bohemian equal male female mob of young, mainly Glaswegians and what is, Glaswegians are a bit further afield but what is very interesting nowadays we had an event in the building, I have to remember two years ago, year and a half ago, year and a half ago where we called it a Mac memories tea party. And there was in the technical education room on the way into the building we had two or three rooms which were not within the construction site and they were well not within the active construction site and we had lectures there for students and others. But we went through the alumni roles of the school and found everybody that was born basically from I think it was the mid-twenties. So we went through people and found the oldest people looking backwards is what I want to say. And we had three, we had five folk in the nineties, we had a range of people in their eighties and then we went to the mid-seventies and we sent out invitations to come into the building and to talk about their memories of the Macintosh being a student in the Macintosh building. And it was an extraordinarily privileged event to be part of where folk came in and they brought their degree show or their piece of fabric that they had taken for their dissertation but in the day it was a diploma not a degree. And they brought in their workbooks and photographs and they met people they hadn't met for maybe 60 years. It was a really wonderful occasion and we had facilitators on a table of about five or six people a piece and we just listened to them talking. And none of them had a photo of the toilets which was really annoying. And that was the one thing I kept asking any news in the toilets yet but nobody could have that. But we're losing the memories of the building and it was really important to us to try and capture some of the things that were interesting. But colour in the building for instance, everybody thinks it's a black and white building but there was colour in the building. And Audrey Gardner, if anybody knows, is a member of various societies and lives quite near to me who's in the mid 90s now. She came along and she told us what a particular piece of joinery in the big studios was for which I don't think I have an image of.  We'd found a whole area of racking and we kept on uncovering things through the building which had just been happily encased rather than taken away over the years always. And she just said it was because we worked in easels in those days. We didn't work as artists on the wall like you do from the 60s onwards in those days. We still worked in the middle of the room, not on the edges of the room and worked on easels and at the end of the day at the end of the class you'd have a wet oil painting. You couldn't leave it there because somebody might come in in the evening so you put it into these kind of slots that were flap down slots then you put them in but there was lots of air around them and then the next day you'd come in and start working on it again. The things that had been kind of forgotten. That was the basement floor. When you got to the ground floor again you had male and female cloak rooms because again Newbury was really interested in having male and female teaching. Here you have the architecture studios at this level coming in also where he felt architecture should be a very functional discipline sitting at the ground floor of the building and he progressed from junior architecture there and that long run of studios there on the right hand side with the mountable walls between all of these where you could take them apart and run through into larger spaces into senior architecture and only very few people made it up to that senior architecture. You can see the proportions are about a third would make it. It's not dissimilar today architecture is still a really cruel industry to get in. You see in the space of the two gray areas at the top of the site these are the top studes 8 and 11 because he was working on a very tight site and he couldn't build everything to the depth of the site. He knew the sites of the south which is 02 and another night club now on Suckey Hall Street were going to be built so what he did was he put them into the ground but he gave them top light and they were two very very beautiful studes. I am talking in the past sense because I know they've been horribly damaged as well and when you move up to the first floor again you've got these. These are the fine rooms the grand rooms they well not in any ostentatious but these were the ones with the light so they had top light from these roof lights and again these were the library and the museum which is the exhibition area and the design room were as well. So that's the big line of studios and at the very top you've got the the professor studios and the embroidery room which was actually strange enough. My favorite I'll show you a slide of it my favorite room much altered because they had taken the corridor when they built the Henry. They had built the corridor you see there just above composition room and taking it all the way to that doorway because otherwise you were walking through a class and it did at least spot that very beautiful room but it was a schizophrenic building. This was his elevational plan at the time back in 1897 and at the time he figured that once he built the east elevation on the left there which is very much as it is today minus a few bits he would do the same on the west elevation. That was the one he presented to the to the board of governors at the end of the 19th century. They didn't have the money and they said well come back and do it again by the time he came back to do it in 1907 10 years later the library on the right there was utterly different proto modern soaring jazz modern doorway down in the middle of the bottom there and just extraordinary use of I mean this is a building looking to the future. It's not about it's not about anything to do with any arts and crafts even in that sense he's absolutely heralding modern architecture in this elevation and it's the most extraordinary elevation still to look at. As I say in the first file that was the one that was most severely damaged and at the back well where does that start you know it's a fantastically mad building all the windows in the building. There were some that actually matched up but so many different windows in that building in each window every single window always had an opening pain. If it wasn't a whole casement it would be one little pain in the Henry had one pain that opens every window always went through the building was constantly getting through it and breathing and you see what he's looking at 30 years later when he's looking at castles and this is the summer palace of the Queen of Aragon in the Pyrenees. And you know what was in his mind he's thinking about Scott Peroni was a great nationalist about Scottish architecture and castellated architecture generally and he felt Scotland should reclaim its own I think and develop its own type of architecture but also very much looking to the future. The reason I put up some of these wonderful images and these are still with us thankfully these images these are the things that really guided the first restoration project to the detail that we could move to. So the logia on the top right there the lecture theatre down below both of these are these lovely setback spaces and again Mackintosh I think as a man had this wonderful forward thinking attitude and understanding I think about how an art school would work. So there's a lot of talk nowadays about if you go to Google's headquarters or Apple Mac's headquarters they have bean bags and shoots and you know places where you just have incidental chats in a corridor and a cappuccino et cetera but Mackintosh was doing this over 100 years ago so in the logia you've got these little setback bays where you just have a stool and put a little shelf you can pull down and work on and again outside the lecture theatre he could have done that as a straight line but he's just made these scalloped benches and this appears if anyone remembers the main one. I mean library corridor with the fantastic full height timber booths where people sat and smoked all day until reasonably a long time ago. And then the library and this image of the library was taken we can actually dated almost exactly as to when it was taken and it was about 1909 in the August before the main periodical table arrived because they're using a different that some of the furniture hasn't arrived at that point we've got the bill of quantities and the job book. The furniture arrived but the chairs are what he had specified for the space and it was really after the first fire when this room was utterly destroyed apart from the metalwork these photographs were absolutely essential it allowed a team a very young team from our architects page and park and two people in particular to work on this to the nth degree to the point that they could look at the archaeology on the site images of it that had been captured. Videos obviously and what remained of the library itself and be at the end at the point we were installing the library which we were just before the second fire and they would say stand up in a lecture theatre and say they felt they had 98.9% I don't know why that but you know there was always but you didn't quite know which would normally be behind a book a book case or something like that but generally speaking they felt they had knew exactly how that library being built from the evidence that we had from photographs such as this and what you what we. Know now is if you see the far column I think people not people but you know there was a kind of common thought at the time these were great big stansions of beams of wood that went up and held up the balcony but what we know now is that very cleverly we know in again in the job book that Macintosh had wanted it done in oak and he'd said it would cost 400 pound more to do it in open pine and he wanted oak and the Board of Governors at the time said well we'll think about it son see how you can make savings elsewhere and then he didn't. So they said we can't have oak but these are in fact tulip wood and there's a piece of a square piece here a square piece there a piece of cheap pine running at the middle a plate of tulip wood and another plate of tulip wood they're very very thin like almost a veneer so they do look and tulip wood has the. Which is from the North East Sea Buddha of the United States tulip wood would have been a very readily available wood at the time also one that is known to be the softest of the hardwood so it can be chameleon like it can do what you want with it you can kind of twist it into what you want and it takes a color very very beautifully it's very even grain and it could be stained to look like oak so he used a kind of a slightly you know chameleon wood I suppose and he did make that building look like an oak interior but and you can see from that again if. Remember before 2014 that the library was very dark space but it is actually quite a light finish on that so when we were doing the research on it we found that it had been actually a blend of almost oil paint almost an artist oil paint that doesn't exist anymore in professional painter and decorators kit of parts but it was a pigment oil that you could rub into the woods it wasn't paint it wasn't stained but it was like something you'd squeal out of a dail around the tube in those days you'd get in big vats and I think they can still get it if you. Ask for it from places like what are they called Elliot's is it on Finnison Elliot place that the paint mixer up a who'd be we're around at the time in fact on the map was built an incredible industrial institution that's still over in Finnison in the West End and these images again very helpful to us at whatever stage we are top right we've got studio 11 one of the top lit so the top left and then studio 58 here again top top lit and light from all four sides in that particular. Tower the tallest part of the building so we look at these and look at what he was doing with lighting which was really clever at the time so he uses a lot of bear bulbs he's celebrating the fact you know he's got the mod cons he's got the electricity it shouldn't be used too often but he but he's definitely saying here it is I don't need to press these up this is fantastic but what he is doing in the in the top studio then modelling studio is these are on a system of runners called the Laurie and Engelfield system which again we found a patented system but very very early. The use of it and particularly in a scene such as this and what you could do is pull them across on wires and group them over a particular object you can lower them you can tilt them you can add shades them like the top left shade has got so you can focus beam of light on something so the students can actually work on a piece or scatter and work in the far corners. It's very simple it's just a bulb on the end of a wire but the way he was using it and manipulating it was absolutely innovative of its time and of course very very she she in vogue-ish now if you go anywhere and look for LED lights which are all the spare bulb technology as well. And the bottom left is the embroidery studio selling about so that's the one at the very top of the building that got added in 1909 when they took the roof off and what I love about this is the fact you've got three different types of window opening. You've got the top lantern light going north and then you've got south light and he was constantly modulating light so that the south light would have been absolutely harsh at times so he's punching the holes in that rear castle elevation and then you've got this lovely grid window down at the bottom as well. Of course that room has never looked like that for a long long time not long after they continued this corridor and took it right the way to the door at the far side so it blocked out that light from that side and that's a potential opportunity for us going back having is now no longer. Whether or not we put that room back and have that fantastic three point of light type of light coming in which personally I think we the school should do. Anyway to take us leave us forward a little bit. That was the opening of the reed in March 2014. Everything was good. We just had the new building. It was an international American competition winning design for the School of Design so that's the School of Design on the right is the School of Fine Art. The board is where that photograph is taken and that's the School of Architecture so we have this tight wonderful campus a new public realm betwixt. On May 23rd that was the first fryer but the fabricated put it out at that midpoint. They were pretty heroic and I say heroic because not just because they did their job but they went back in and they rescued the archive which is essential for us and they rescued the furniture gallery and they rescued a lot else beside and they helped students go in because it was the start of the degree show. There was a lot of devastation at the time that was the hen run. That was the library but we could stand on a floor and look in at the library at that point and that was it when all the archaeological excavation had happened within the space and the ladder beams had been put up around the windows which were again badly damaged. These are these pillars which we began to unpick and realise how they've been put together and made. Once the building had been cleaned and taken back obviously a lot of sadness and a lot of loss but it was still substantially there and it was very badly beaten up in that corner indeed. You can't underestimate the loss of both the library and the store above which had furniture and paintings in it but it was a 20% of the building probably is what was affected and even then there was survival. This is from the library extraordinary in the inferno that it was but still some things had survived. The textiles were down in the basement and the whole archive was evacuated thankfully so everything came out and they were dried across the road in the reed building before being repackaged and put together. It revealed things to us because I mentioned about the walls in the studios that were removable and the old planks you could see it's not actually quite fuzzy but what you're looking at there is these walls over the years as Macintosh had designed are just single planks that go up to a down stand where the lath and plaster is above but you could take them out so you could move through one room to another room to another room if you wanted to have three large rooms or you could have two and one or three individual ones. But over the years they'd been plasterboarded over and then services had put on to them and fixed in place and sockets so they just fixed into those spaces and then putting the building back we were going back to Macintosh's flexibility again. Very forward thinking very modern in his flexible space where you could just pull back walls and have large events happening in them or five aside football matches or whatever you cared for. And other spaces again this is on the east side so it wasn't affected by the fire you know the stairwells on the right side we had a lot of soot damage but the hard surfaces this is the Glasgow marble so called and it was where Macintosh again working on that budget was doing nothing fancy but he was doing a kind of Roman cement. He was actually known as Keane's cement and it's still called that in America and we'd found out it has alum in the mix and it's made up of quite a rough scratch coat and a very very thin very fine top coat of this Keane's cement which you polish with the pallet effectively and you just get this lovely rendered cement finish so we'd found out how to do that again and repair it and also to clean it. And they're big hard surfaces you know so we could work with them and these spaces again are absolutely sculptural in how he had designed them that's again you can see it's on the east side and that's the matrim window so that if you remember from the animated model that's when he had to add a staircase on both sides for the new floor. So this would have been an outside window it became an inside window but extraordinarily done and I don't know anybody else who could have handed that was such canash to actually build a staircase at the front of your building and make it so a thing of beauty in its own right. This is probably one of the sentiments that had guided us at the first fire in so far as we lost a lot of material but we felt we could get under the skin very much of the man and of his thinking and what the intent had been in how he built the building and that we felt if we studied that well enough and hard enough and I don't mean myself by that but you know a host of people from our archives and researchers and the architects and the engineers. But if we brought that together we could rebuild this building and of course a lot of the questions at the time even more so now were you know do you want to rebuild the library why would you do that because it's gone it's gone it's a moment in time and you'd do something modern now you'd get in a modern architect to do something. And I think the school at the time felt well it had just finished its big you know expedition and adventure into modern architecture with the rebuilding it had got that out of its system and that's sitting there very beautifully. The Mac was a room in a glorious house that it had lost and you wouldn't redesign that completely if you didn't want to you know if you loved the room you'd bring the room back. We had all the drawings as we said at the time Macintosh never actually built it he wasn't the man with the saw or the nail or the hammer he designed it we still had the designs and we felt new craftspeople could do it if they did it correctly and with integrity so that was definitely a guiding light for us. I think it's his own words in some ways as well. So the first thing we did was put a temporary roof over the building at the time we're thinking about that now but there's so little interior left. And then there's two slides which are quite wordy and it's this one and the following one but they're probably quite important. We had to look in terms of conservation just what is the right thing to do and the answer is there's no one right thing to do. It's not it's too complex for that but we worked through one of the best known of the conservation charters and there have been others since certainly but the borough charters still I think holds true very strongly in that you can restore something.  So there are various things there that talk about where you should reconstruct, where you can adapt, where you can insert new work and where you just repair what you've got very carefully and in some cases make it very obvious indeed what you're doing in terms of the repair. And there are various places where we did do repair. The majority of the building was actually repair because so little had been really damaged, a lot of smoke damage but other than that it was about bringing it lovingly back I think. There was a lot of reinstatement of things like for instance there had been lost over the years so the plaster work had been lost in a lot of the studios and in the ceilings where they'd come down over the years perhaps had been put back up in plasterboard or there'd been new services riddled through. And we worked with incredible subcontractors which we'd hoped to have back in and I'll show you some slides to put in some really wonderful beautiful plaster work and those skills are still with us to do that. There was a lot of conservation of fabric we had and the sculptures there which were still left within the building. We lost about three or four the first time we've lost more in this fire because some couldn't leave the building so about 20 to 30 were lost this time. And that's in itself tragic. I mean a lot of these sculptures are held in places like the Louvre. We have a request at the moment to go in plaster of Paris one of their sculptures. I'm sure they'll tell us to take a hike but we just thought we'll ask anyway and see if we can take some moulds. But Edinburgh College of Art for instance they have their sculpture quote and a lot of them are duplicates and they were sent around the art schools at the time but the ones that we had we did a lot of conservation work so I'll show you one again just a little bit later. And some were entirely reproduced. Things at the library were starting from scratch but were being done with such attention and love and we had the new technology to help us through this project which was still is a reserve now of information that's computer held of billions of pieces of data. That have all been put into a computer model which will help us so again that was the view after fire number one the building was you wouldn't kind of almost have known but you could these windows were later additions anyway in the 19 about 1948. They had been hopper windows that opened in and they become casement windows you can see the kind of vertical windows so we were changing those back and those windows had just started to get installed in 2018 to the original profiles and they would have made a stunning new difference I think to the building. Wonderful work at the time all aided by the invaluable addition of the national drink obviously and this was constantly found it was like the traffic cone on Wellington on the site and we kept on taking them away but I think it became a kind of game with the seal guys not the masons they didn't like it but they were winding up the seal. But it was mainly one or two stone masons who were consistently on this job because the main area of stonework damage was over at the library end and some lovely apprenticeship work done as well during the project. So this is the roof going back on in the first project and that was the same room with its timbers going in the fireplaces all it had survived and that was just before the fire occurred. So the roof timbers had been darkened down the chimneys had been plastered again this is the professors studios at the top floor and the fantastic Douglas fir planks beautiful planks which were smooth on one side and rough on the other and the joiners were furious because they were being told to use the rough side and put the smooth against the wall and they wanted but that's how Mackintosh had it it was very rough it was called rough from the saw plane from the saw plank and that's what was being used. This is the roof going on on studio 58 and again extraordinary work here with scaffolders working with riggers working with glazes working with stone masons to cut pockets into the gables working obviously with these fantastic joiners JCG from Dymfirmland and lifting in these massive balks of timber. The harling was being finished using Portland cement again we looked at using other materials but actually the Portland cement worked well and put all put all on together it was it was coming out very very beautifully. Rooms like this again the plaster which is the architecture studio on the ground floor and notice things like Mackintosh and there's no doubt about it his obsession with not breaking the light so those tables will have been designed or specified by him they do not break the sill height of the window. Everything it was down to that level of detail and again his slung lighting but very very simple good and timber floors above with lovely soft plaster work that was it after the first fire so it's still there that was it just before the fire again just lovely plaster going in and ironically and sadly that is the miss suppression system pipes that have to be obviously exterior to the fabric which would have did rather spoil it but were necessary. And if you look at things at Euston station you can see you know he was again very much a forerunner of the simplicity and the beauty of that kind of work. The logia, new timbers going in, glass being put back into logia, the hen run that was it not that was it having been altered you can see the flashing discoloration there at the top of the roof and that's because the roof had been raised because some of his details were not great all the time. And on that one he had a quite a flat roof originally but we hadn't realised it until we took it off and because it had been so badly destroyed and realised there was a lower line to that. And we can see that from the photo on the right so we at the same time found photographs in the archives and not just showed us that the roof was much flatter than the probably better a chedding water version that's on the left. But they also had these lovely converging verticals so not just the wall had had astragals going along it but the ceiling did as well. And what that does is create a kind of infinity tunnel so the whole building very much very much was a tool for teaching you would sit in the corridor and you could draw a vanishing point. And when we started to put all the back again and you can see that with the original pitch put in it still has a pitch but it's only about two and a half degrees not seven degrees. You can see that when the sun's coming through us it's due south you've got a grid there and you can start looking at perspective and how to measure and draw things at a distance. And it was all about teaching you things like this. And again when we started looking at through the archives in the interior now in the Kelvin Hall they allowed us in just before and there was a detail that this is as the building is but we found his drawings in the archive and they actually show this slanted detail at the top there by Professor Studiw. And we thought well that again is a better detail actually that will shed the water. What it wouldn't do is allow the professors to sit there and look out the window. So whether or not there was a change we don't know but certainly the detail was a flat one. And again similarly this is the building after the first fire in studios that weren't affected but there were maintenance issues so that's kind of tape across one of the windows where it cracked and the top of the studios. But when we got into those areas we found that again that grid had been in his drawings and so these were going back in patent roof lights with the grid again. Everything was made up of this square, this module in the square straight in the building. The main corridors were being stripped back to this lovely honey coloured wood which we knew was now the original colour of the wood. Studiw 58 had got new timbers coming in. That was a dark studio and you can see the roof timbers there again. I don't know why but it was darker but the bulks of timber there, the big over 9m high timbers were actually from a mill in Massachusetts that were floor joists and they were brought in to form the beams, the four posts in this very Japanese style studio. And they would have been of a mill of exactly the same date as the building so it felt the right thing to do. And I think I've called that the shock of the new because when that and again you know look at the lightning through of light and the sills there's no doubt there was a lot of discussion of the things at the chairs because the chairs were a little bit low. Not for somebody of my stature but for bigger people, abnormally tall people. They would have found those quite low by about two and a half inches from a standard chair but they were all about fitting against that sill. He worked down from the sill down and that was the height of your chair. He didn't work from the floor up and what your legs were doing. There was nothing to do with that. And it goes over the time that you can see how dark the library is just before the fire. I think there's about 212 this image is taken. And you can see the chairs that had been moved around and switched around a little bit. But this is the prototype bay that we had built by the very excellent Edinburgh based cabinet makers that were doing it. So we asked them to do a full height bay. Now this bay will probably come back to school quite shortly and be put into the re-building. And they'd looked at the analysis of the paint. They'd looked at the carved details and this is the colour the library would have been we think originally. So it would have been shocking for folk to come back into the building Easter this year because it would have looked very different to what we saw there. But we do think that's how it was originally and it would have darkened over time with the effect of light but also through I think the school itself had painted it or varnished it in a different way. And these lovely balusters were coming back as well and these fantastic skills of one man doing all these lovely pendants who's finishing that work anyway. None of the carved detail was brought on site thankfully so that's still out in the warehouse somewhere and we'll come back. So very quickly the second fire was appalling. This is taken from the roof of Blythewood where my office is, Blythewood school of residence by a student. That was not long after the call was made so the speed and the intensity of that fire you see the museum down there on the left with the four people were looking at only the eastern side of the building at this point. But it's an appalling fire, really appalling. And the next day that was the scene from the air, the entirety of the building and the O2 arena as well. You can see the circular form behind it taken out. We were very quickly on the scene with the scanning equipment that had happened in the first fire. Now much augmented so we were very quickly able to say if the building had moved anywhere it had in one or two areas. So this is all point cloud data from lasers that's been fed out, brought back in, compared against the building from before. And very quickly a massive amount of scaffolding was put up to hold it both on the outside and from the inside from any kind of collapse. That's the damage to the library windows that have been very beautifully restored and finished. The windows were going in so the Italy shattered. This fire didn't just burn on the inside it burned everything. It was burning stone. So we are very speedily the wonderful man who works with me called Tom Simmons who is in charge of craft skills and training. He became overnight the salvage operator and has been cattle tagged here. If you can think what they look like, tagging every bit of stone that's coming off the building, every piece of metal. So that has barcodes and we're plotting where they come from, where they would go back to. If they are capable of low down the building that fantastic jazz modern doorway is still good. It's the only bit that wasn't damaged at that lower level. Inside, as I say, the only thing that survived, the fire brigade didn't put this one out. It stopped finding anything to burn. So that is the horror of the inside of the building. The brick is done alright because brick is made by firing. But you can see even the steel has given way to the pressure of the heat and the stone is appalling. There will be fine. So in the first fire there were fine. In the library we found the lights. These are the art school. This is after the first fire. We found these little flat packed bits of metal. We did it on a grid at the time through an archaeological survey. Those were the rights when they were in situ. We packaged them up so we gridded where they were found. Then when we got a kid apart we thought probably because a soul double melted. That all belongs to one. We found most of the lights. I think in the end of the 53 lights 17 are composite. But most of them are complete sets of lights that we were able to bring back to. Absolutely. It's not a terribly good image but the one on the right there shows you the lights coming back and then they are burnished up again and the new pieces being made there. But they will come back and look like they're new. The brass is extraordinary. That level of attention and detail, things that the furniture of it hadn't gone back in. It was being made off site so that that will continue. We won't be putting back in the mix and match chairs that were there. Just one that we thought were original. The clocks are off site in the archive. We lost two in the fire I think so they're being remade anyway. I think I'm on the last few slides actually. Leicun was one of the sculptures that you can see was very near the first fire. He's been lost in the second fire which is terrible. We had digitally scanned him and you can do as a project actually. So he'd been wonderfully restored and we were keeping the black because we felt that's how he'd become. He had been painted white all his life as a capacitor cast but after the fire he was very much damaged. He was wonderfully captured on film actually having. The way that Graciela Ainsworth, the wonderful Edinburgh based again conservator that was working on this had to do this because you didn't know how much damage had happened on the inside. One of the studios, this particular studio was set up when you're in a hospital ward, you get those things, you move along with the sale line drips on it. So they had epoxy resin or a form of consolidant that was being pumped into him and he had those by the side of it. So it was like an A&E ward. All these sculptures were these things in their veins being consolidated from the inside. But unfortunately he was finished. He was almost certainly lost in the fire from what we can tell. He's not sitting on the floor because the floor doesn't exist anymore. He was captured through a wonderful virtual reality project. And I've seen it and you put on the virtual reality goggles and helmet and you can still walk around him completely as if he's right there in the room. It's a very emotional experience. And what was interesting at the time was Lacune. This is at the Vatican. He's meant to be the embodiment of human agony.  And we always thought he was marble and that's where the school always had in white. But in fact he was originally a Mesopotamian bronze.  So we can remake him if we wish to. There are copies. This is a little project one of the students did. So we have on the right hand side a latex 3d print out from a machine because we've scanned him. One is an actual plaster cast. One is done in bronze. One has been done in plaster and then blackened and whatever. But plaster casts are something we are able to bring back to the building. It's more about the spirit of the building I think as much as a lot of the things of the building. So finally I just wanted to end on education I think. One of the things that we were told by the now director of the school. So I will dump her in. She used to say to me because she was the head of the design school. You don't need flow sockets. Students hate flow sockets.  And of course we were having to put a huge amount more services in the building to accommodate what people now need. Which is a phone charger, a computer charger, a camera charger, whatever. And just everything on your desktop. And she kept on saying to me by the time it's finished you won't need plugs at all. It will be all in the ether. It will be a walk in and everything on your charger. So it wouldn't have in a couple of weeks time so she was wrong. And we did put sockets in. I kept on saying to her well if we don't need them we won't use them. But in four, five years I mean the programme we are looking at now is 224 before the building would come back. It is really genuinely likely that we will not be using sockets. There will be by that time the pace, the race of technology is actually far greater. We have opportunities by putting this building back which I would love to do that room if we are going to do it. This was one of the studios we had. It wasn't even a studio. It was the old counselling suite that we had finished. And you can see the amount of wiring that was having to go into it. Just the service of building nowadays. I'd love not to have to do that if it were possible and to keep it clean. Mackintosh himself, I just want to end on a way because I suppose I started with it a tiny bit with the murehead bone print. And Glasgow in its soot and its smokiness which I suppose nowadays is probably what you'd see from space if you looked over Saskatchewan or something like that with all the fracking and things like this with all the environmental changes and challenges that we have. I think he was without doubt an environmentalist of his time. He greatly believed in the natural and the botanical and the living world, I think. And I think we were already looking at, that's taken off the time when the radiators were on. We were already looking at, we were underflow heating the library. We hadn't double glazed the windows. That was not appropriate, I don't think, but there were areas where we were using similar double glazing. We will be able to do a lot more this time because there's so little, or we have the skeleton of the building left to actually make this building energy efficient. And it would be wonderful if what we could do is actually look at this building and if you look at what is happening through educational and through research institutes at the moment and the speed of technological change about things like the glass can now absorb the sunlight and send it into energy through the building. Even the render, the render on the back, there's an incredible building called, I think it's Laplazzo Italiano in Milan, which if anyone's seen it is like a concrete forest. And it's made of concrete that in itself takes the pollutants out of the air. So it takes 70% of the pollutants out of the air by the way the concrete is put together. You can get concrete now that absorbs CO2 in the manufacture of it. So it actually isn't carbon neutral, it's carbon negative. It will take carbon out of the air in the way that we want the Amazon rainforest to do. So we should be looking at all of this. We've got solar voltaics, we've got water recovery. There's a huge amount plus robotics, which I don't want to get into particularly, but certainly the technology of even the construction industry so that instead of trying to think about what should happen when and the sequence in a programme, that can now be fed through incredibly powerful computers on some of the largest projects that are happening over the world to tell you exactly when your supply chain needs to come on site to absolutely minimise construction waste to run the project. And you still need the human eye and the experience, but the intelligence of that system now is something that we would be embracing, I'm sure, in a few years. So I think just to end actually, and it's actually remarkably going to be on time, I think without education, inspiration, innovation is going to be the future of bringing this building back. But what we will never get around is the creativity, I think, of what people, actually just people will bring to this and the integrity of the process. So it's the marrying of that, I think, that will avoid catastrophe and that will be hopefully done through the powers of not just the art school, but the wonderful experts that have come around and the people who still love what we have left of this building. So thank you very much.


So, here we here is where we stopped right we said that intensity is A star into A A star and we said that provided the result first we said that when you lock n number of modes together so that their phase difference is not a function of time then you get pulsed operation repetition rate is not a function of number of pulses that are locked pulse width is that is an important take home message. So, repetition rate is 12 by C all that is important there is what is L, L tells you what the repetition rate will be right but pulse width that is where number of modes coming. So, now let us see how so we start our somewhat sketchy discussion of modulocking I apologize for the quality of slides slides that will uploaded will hopefully be better I tried to do things quickly and this is another moral lesson that you do when you try to do things quickly they do not work out to be very good ok. So, as we said in the previous module we do not really have plane waves we have damped oscillation but then eventually the way we go from time domain to frequency domain is Fourier transformation and the beauty of Fourier transformation is that to get the correct information about frequencies it does not matter if you take a plane wave or a damped wave because they get separated. So, that makes the mathematics a little easier otherwise we will have another damping factor here. So, we are going to work with plane waves where we will say that this electric field is a function of time and is given by E0 the amplitude maximum amplitude into e to the power i omega t what is omega yes angular frequency omega is angular frequency what is the relationship between omega and nu frequency and angular frequency 2 pi now just all you have to know is whether to multiply by 2 pi and divide by 2 pi it is not very difficult right I think we know it ok. So, now what I am saying is I have locked these modes together and I am saying the number of modes that I am working with capital N is equal to 2n plus 1. So, I am working with an odd number of modes because the math becomes little easier as you will see in the next step if I have an odd number of modes it does not matter even if it is an even number of modes you can conveniently neglect one right because remember how many modes are we going to have 5000, 6000, 10,000, 20,000 something like that ok. So, it does not matter whether it is 20,532 or 20,531. So, we formulate using 2n plus 1 number of modes ok. So, here we are saying that from one mode to the next there is a difference in frequencies right and we have worked out the expression earlier what is delta nu delta nu remember delta nu what is delta nu it is difference between the frequency of nth and the n plus 1th longitudinal mode what is it what is the expression C by 2L it is going to be handy remember do not forget that is very important C by 2L which is inverse of round trip time you told me right C by 2L. So, what is going to be delta omega what is delta omega going to be you know delta nu delta nu is C by 2L what will delta omega be that factor of 2 pi will come right we are going to use this. So, do not get confused. So, this is what we are writing is 0 into e to the power i omega 0 plus k delta omega q ok t what is k is a number that varies from minus n to plus n. So, now you already see why 1 2n plus 1 number of modes it becomes nice symmetric symmetrically distributed about a mean about central position not mean central position ok plus we are saying k into delta phi q what is this delta phi q phase difference and that is independent of time let us remember that that is very important. So, how do I expand it I can well e to the power a plus b is equal to e to the power a multiplied by e to the power b. So, I can use that and I can take this e 0 e to the power i omega 0 t outside the summation and then inside I am left with e to the power i k delta omega q t plus k delta phi q I have to do the summation. And now the advantage of summing here it is not showing, but advantage of summing k from minus n to plus n is that I know what the answer is. So, these summations I mean I am sure we might have done many of these in 11 12 maybe in BC or something right the summations are all nicely worked out and it is known that sum over k equal to minus n to n e to the power i k alpha is equal to 2 multiplied by sum over k equal to 0 to n cos k alpha minus 1. And then this you might think one summation is leading to another summation. So, what is the big deal the big deal is that this summation is also known as you are going to see, but let us first write it this is what it will be you have this outside the bracket inside the summation of exponential terms becomes summation of cosines. And also sum over this domain changes right it was minus n to plus n now it is going to be k equal to 0 to n. So, if you took only capital N then we would have this trouble you cannot even write n by 2. So, that is why we want 2 n plus 1 modes ok. So, now all we need to know to go further is what is the summation of cosine terms this is the summation of cosine terms does it look very nice, but that is what it is what can we do right. So, I am going to rush through the next steps you can do the math if you want it is not all that difficult. So, this is what we substitute we substitute for the summation and then we put alpha equal to delta omega qt plus delta phi q. So, in terms of alpha this is the expression that we get ok. You get something like E0 e to the power i omega t and you understand that the moment finally we do not want to work with field right we want to work with intensity. The moment we want to work with intensity this e to the power i omega t is just not going to be there because we will multiplied by its complex conjugate that term is not going to appear. So, eventually we do not have to worry about it we do have to worry about this sin 2 n plus 1 alpha by 2 divided by sin alpha by 2 this term ok. So, let us write it in a little easier form what is 2 n plus 1 2 into small n plus 1 what is that 2 n plus 1 what is that number the answer is there in the slide here total number of longitudinal mode side. So, the other way we write it is capital N. So, now we have the job of the small 2 n is small n is done let us write it in terms of capital N and this is what we get and here on the quality of slide also the starts getting a little better ok. So, we get E equal to E0 e to the power i omega 0 t multiplied by sin capital N multiplied by sum of the sum of delta omega and delta phi divided by 2 yes. So, you have to consider that all at all frequencies the contribution to the equitability set that will be 0. Yes. But equitability. So, as I said eventually it will not matter because you are going to do Fourier transformation right you can add on the amplitudes at that time that is true but then there is a way out there ok. So, this is what we end up with the form of function is something like if you are talking about intensity sin n x by sin x whole square ok what is x is this delta omega t plus delta phi divided by 2 and plot of sin n x by x sin x I encourage you to do it using whatever graph plotting software you want to use you see this is what you get and this is a kind of function that we encounter everywhere whenever we use optic. One thing we should not forget is that this is a periodic function I have drawn only one but it is not going to be one it is going to repeat. So, you are going to get this and this is what I was saying that picture we drew earlier was not completely correct in the sense that you do not just get a pulse you get like this small you can call after pulse if you want ok. But the issue is even this picture is drawn using a comparatively smaller number of smaller values of capital N when we really work with ultra short pulses this duration is so small that in the same scale it is very difficult to see capital T and T P you get to say T P only when you zoom in to into one pulse ok. So, this is what it is. So, do not forget what is the x axis what is the y axis here. So, this is what you get now I have given you the answer already. Now, let us see if we can deny it. So, first let us worry about repetition rate what is the meaning of repetition rate we can say it is time between 2 maxima where will the first maximum occur sin square n x divided by sin square x where will let have maximum value of course, for that we need to work out limits and so it is difficult right because it is some it might sound like there is a discontinuity when x equal to 0 but it is a removable discontinuity right this point here if you think that point is going to be actually 0 is not it 0 by 0 kind of situation not 0 sorry 0 by 0 is what you will get but that discontinuity is something that you can remove. So, first maximum will occur where delta omega q T 1 plus delta phi q equal to 0 where will the next one occur second maximum. I will give you the answer when it is 2 pi does it make sense right ok just plug this into this expression and you will get the answer at 0 and at 2 pi. So, now if I ask you what is capital T capital T you can get by capital T is basically T 2 minus T 1 ok and since it is a periodic function this separation will be same for any pair of consecutive pulses you take right. So, what is T 2 minus T 1 the subtract delta omega q is constant so what do you get if you subtract one from the other you get delta omega q multiplied by T 2 minus T 1 and now see delta phi q would cancel each other the moment you take a difference that is exactly what will not happen if delta phi is also a function of time right you can do this only because delta phi is not a function of time and it is constant everywhere. So, what do you get delta omega q multiplied by T 2 minus T 1 is equal to 2 pi and what is that T 2 minus T 1 that is capital T time between 2 pulses this one occurs at time T 2 this one occurs at time T 1 ok x axis is time multiplied by something right from there you can always convert to time. So, T 2 minus T 1 is equal to capital T. So, I can do it like this difference in time capital T is equal to T 2 minus 1. So, you get delta omega q multiplied by capital T is equal to 2 pi. So, what is T 2 pi divided by delta omega q right now again we come back to what we promised is going to be useful later on later on time has come what is delta omega q delta is difference omega is angular frequency. So, it is difference in angular frequency between what and what 2 consecutive longitudinal modes very good and you already know some quantity associated with it we know delta nu and what is the relationship between delta nu and delta omega we know that already right. So, what we can say is we can write something like this 2 pi divided by 2 pi into delta nu q because delta omega is equal to 2 pi into delta nu when you go from frequency to angular frequency that factor of 2 pi comes. So, you are left with 1 by delta nu q what is delta nu q yes. So, now from there you get 2 L by C right. So, we see that this repetition rate that we get has nothing to do with how many modes are locked that is the nice thing that comes out because otherwise it would have been a problem how do you decide how many modes are available for you and you decide one thing that is there is what is the spectral bandwidth say to start with let us say your spontaneous emission spectrum that is independent of anything else spontaneous emission then remember we had drawn a laser threshold where half width was delta lambda right. So, where that laser threshold will be who determines that if I can somehow increase decrease the laser threshold then I will have more modes that will get locked are you following what I am saying this figure this here is your laser action threshold okay. Now what I am saying is my first thing that is important is which substance what is your active medium that would better have a broad enough spontaneous emission band okay then what I am trying to say is here I have placed the laser action threshold here is it in any way possible to push it further down remember laser action means you should have stimulated emission is there any way for a given substance that I can increase the stimulated emission bandwidth how can I do it exactly pump harder if you pump harder then this threshold can actually go down okay there is more molecules will be excited and so on and so forth do not forget the stimulated emission is like a bimolecular reaction right bimolecular elementary reaction between light and matter. So, you could think of doing that okay so that way you can get more longitudinal modes and you can try to get shorter pulse that is why in a tricepher laser you want to pump with a high energy you want to pump if possible by 5 watt instead of 3 watt you want to pump if possible by 8 watt instead of 5 watt to get shorter and shorter pulse of course there are other issues damages an issue so you have to take care of those but the problem is if the repetition rate also depended on number of modes they would have been an issue is not it then you will you do not want the repetition rate to change otherwise synchronizing electronics everything will change so it is good that repetition rate is just 2 L by C nothing else matters how hard you pump nothing not so for pulse duration okay so for pulse duration it is not very difficult to understand that what happens let us start thinking a little qualitatively let us go back to this analogy of people running around a field. So, when they come together that is the pulse maximum right if you want a pulse of short duration then they have to scatter faster okay now if you have more and more people running with different speeds will you agree with me that scattering is more efficient there yeah in fact if you look at this interferograms where you mix many waves you will see that more than number of waves sharper is the falloff right that is why you need more pulses to get a shorter pulse duration that is a qualitative understanding now let us see what we get from here okay how do I define pulse duration as we are see practically we always talk about full width at half maximum and when we finish this discussion today we will be talking about full width at half maximum but for now it is easier for us if we consider all the normal modes that are there otherwise again pulse shape and all that will come if you want to consider all the longitudinal modes that are there you want to go from here to here right. So, let us see what is the time about this big maximum where your intensity becomes 0 before and after okay difference between these two times is going to give me pulse duration remember this pulse duration is not full width at half maximum. So, if this is 200 because again that means 200 femtosecond then full width at half maximum is perhaps 100 perhaps less depending on the shape of the pulse okay and this is the shape of the pulse also becomes important right if you want to go full width do you agree with me that ratio of full width at half maximum and full width that is a 10th maximum is not going to be the same for a Gaussian pulse and a Lorentzian pulse right will be different. So, right now we do not worry about all that we just talk about the pulse duration. So, when will they become 0 when the numerator is equal to 0 and the denominator is not. So, that condition is sin n delta phi t plus delta omega t plus delta phi by 2 equal to 0 okay this is one condition where sin x equal to 0 when when x equal to 0 next time when does it become 0 yeah pi okay. So, I can put time as t1 I can say this is t1 for t1 this thing is equal to 0 for t2 the next one it is equal to pi. So, again from here you can find out t2 minus t1 very easily and that is going to be tp the pulse duration yeah. So, do it this is what you get tp equal to t2 minus t1 just subtract what will you get you will get 2 pi divided by n delta n delta omega is that right yeah just simple algebra right. Again delta omega what does by now we are sensitized to this issue whenever we see delta omega what should we do and here this is 2 pi divided by delta omega it is even more tempting go over to delta nu and you know the expression for delta nu it turns out to be 2l by nc. So, just this n is different so we are vindicated you need more number of pulses so that this more number of not pulses sorry more number of longitudinal modes because it this n comes in the denominator okay larger denominator smaller tp that is what you want right. But then we might as well have stopped here if you wanted to have only theoretical but finally we want to go over to something that is more tangible who is going to count the number of longitudinal modes it may not be all that easy okay but there may be something else that is easier. So, let us use another expression and you might have forgotten because we have talked about it I think couple of modules earlier remember this in fact we talked about it at the beginning of the previous module as a recap we worked out that number of total number of longitudinal modes capital N is given by 4l delta lambda divided by lambda 0 square okay. So, might as well substitute this so when you substitute what you get you get pulse duration is equal to lambda 0 square divided by 2c delta lambda okay. What is delta lambda in the treatment that we have followed delta lambda is half width that half maximum of the spontaneous emission band. But what is more important for us is that it is the half width at the base of the stimulated emission band half width at base yeah okay. So, now we have something tangible right we can measure spectrum when we measure spectrum we know what lambda 0 is we know what delta lambda is so it is not very difficult to figure out what the pulse width is going to be that is why in our lab we do not bother about trying to measure the pulse width in time domain. As I said shortly we are going to discuss how to do it see what the problem is we are talking about short pulses 100 femtosecond 50 femtosecond 6 femtosecond how will you measure you cannot see it on an oscilloscope directly okay. So, you have to apply some kind of a trick and the trick that is applied invariably depends on some instrument that was made long long ago okay. Let me digress a little bit I love digression what is the speed of like is that large is that small how do you know it is correct who told you that that is the speed of light I mean textbooks told you but how do they know somebody must have measured it right. So, if I want to measure what is the speed of somodipto it is very easy I can do it using perhaps my wrist watch who what is the wrist watch or what is the stop watch that allowed somebody to measure the speed of light again everybody has studied in the 19, 11, 12 sometime in physics Michelson interferometer the moment I say it you will know it is just that you might know it as Michelson interferometer Michelson interferometer right. So, in Michelson interferometer if you remember monochromatic light was used and there was a relationship from which you could find out the from path length. So, basically what Michelson interferometer does is it degenerates a map like we generate a map of the fluorescence decay that takes place in femtosecond by monitoring second harmonic intensity as a function of delay time. So, Michelson interferometer also generates a map okay and it sort of stretches out does not stretch out it we have sense if it stretches out and creates a wave whose wavelength is correlated with the wavelength that falls on it okay there is a relationship it is not very difficult to work out. So, that is how speed of light was determined. So, now once you know the speed of light you can determine small times using Michelson interferometer kind of arrangement we will talk about that but it is a little cumbersome and I do not know how many chemistry utter first labs in India at all have what is called an autocorrelator it is called an autocorrelator the instrument by which you measure the pulse width is called an autocorrelator and we are happily working in this field without ever having had one why because this is our saving place Tp is 4L delta lambda divided by lambda 0 square. So, if delta lambda because if delta lambda is of some value in principle we can calculate what the pulse width is right if you do not want to calculate what the pulse width is we can get some qualitative value we know from our experience that for a 100 femtosecond pulse laser your full width at half maximum has to be 12 nanometer or so. For the amplifier which is shorter pulse laser full width at half maximum has to be more okay this is a relationship that one can use and work happily in an ultra first lab without ever having to buy an autocorrelator fine. But then it may not be as simple as I have proposed it to be because do not forget what this delta lambda is it is the basal width right one thing that we have not considered so far at all is the spectral shape that is actually important. So, let us close today's discussion why talking about it. So, what we are essentially talking about is transform limited pulses and I have goofed up a little bit on this slide unfortunately bear with me see what are we saying we are saying that a broader spread in wavelength and therefore energy corresponds to a shorter spread in time okay that is essentially something that is absolutely correlated with uncertainty principle once again. Greater uncertainty in time is associated with lesser uncertainty in energy and vice versa okay. So, these are called transform limited pulses of course this is the best case scenario you might have a bandwidth full width half maximum of 12 nanometer but not 100 femtosecond pulse if something else is wrong right now we are talking about the best case scenario. So, let us see why they are called transform limited pulses let us start talking about a Gaussian pulse in time domain okay this is a Gaussian function if I want to know its spectrum if I want to know what that pulse looks like in frequency domain what do we do we do Fourier transformation and when you do Fourier transformation what kind of function do you get another Gaussian okay and this thing that I had by mistake written earlier is that full width half maximum delta omega full width half maximum that is given by this kind of function okay what is the spread in time for this Gaussian function in time the spread is given by 2 tau square root of ln 2 alright now if I multiply that 2 together full width half maximum in time domain multiplied by full width half maximum in frequency domain what do I get I get 0.441 so all this tau and everything cancel of ln 2 is a number okay. So, a transform limited pulse which is Gaussian is going to obey this so if your pulse is Gaussian then it is very nice again no need of an auto coordinator the only thing to remember is you should talk about delta nu not delta lambda okay lambda is an inverse scale right that is why that lambda 0 square factor comes so delta t full width half maximum in time multiplied by full width half maximum in frequency gives 0.441 for Gaussian for a transform limited pulse so what is that why do people buy auto correlators in the first place so far I have told you that we are happily working without an auto correlator without having to spend those few lakhs of rupees that are required to buy it or build it why do people buy at all they buy it because not all pulses are transform limited pulses this is sort of the theoretical limit okay and then let us now close by showing you something else this number 0.441 that we got why did we get 0.441 and 0.8 because we worked with Gaussian function okay so similarly this has been worked out for other pulses as well and these are the numbers forget about this for now for a square pulse the product has to be 1 for a diffractive pulse 0.86 Gaussian we have discussed already for hyperbolic sake these are all different shapes right and there is no guarantee that one shape that always you are going to work with Gaussian kind of pulses Lorentzian 0.221 see Gaussian and Lorentzian we are very familiar with see the differences one is half of the other exponential two sided exponential the product is 0.142 right so depending on what kind of pulse you have what kind of spectrum you have in principle you can work out the pulse width if you just look at the spectrum provided you are working with transform limited pulses okay so that is what we wanted to discuss today next let us see how to achieve we have talked about modulocking we have talked about the theory but how do you do it that is what we are going to discuss in the next few models


How many life changing decisions could you have made in your life that you decided to play safe instead of deciding to step up into your own personal power? Today we're going to talk about how to step in your own personal power and one thing I'm going to talk about is decision making. How to make number one quick decisions and number two how to make powerful decisions that come from a place of growth and not from a place of fear. And so you have to think that for any massively important decision that you make in your life, a decision where it's going to be something that could change your life, but then also for a lot of very, very small decisions, there's only one of two places that that decision can come from.  So if you look back over your entire life the things that you've done, the things that you haven't done, the decisions that you've made, maybe decisions that popped up of should I start a business, should I not start a business, should I marry this person, should I not marry this person, should I break up, should I not break up, should we have children, whatever it is. When you look back on the majority of the decisions that you've made in your life, would you say that those came from a place of fear or that they came from a place of personal power? Think about that for a second. When you look back, would you say that more than 50% came from a place of personal power or more than 50% came from a place of fear? And the one thing that I have found is that for most people, the majority of their important decisions that they have in their life actually come from a place of fear. And what do I mean by that? For me, I know personally that for a really long time all of my decisions came from a place of fear. Staying inside of my comfort zone, not wanting to step out of my comfort zone, not wanting to challenge myself, not wanting to push myself, wanting to take the easy route. I had decisions that were based in my comfort zone to stay inside of my comfort zone because it's easier to just stay comfortable than it is to push yourself. So for me, I know that the majority of my decisions for a very long time came from a place of fear.  Just think about that for a second and answer it out loud to yourself. What I have found is that most people's decisions actually come from a place of fear. Like for instance, should I start a business or should I just continue to stay at this job that pays me a salary? Most people usually stay at that place where they give you salary just because it's easier. And do you think to yourself, oh my gosh, I don't know what's going to happen if I do know that I'm paid every two weeks in this job. But if I leave this job, I don't know what's going to happen. I don't know if I'm going to get paid every single week. I don't know if my business is going to succeed. I don't know if it's going to fail. And when you start thinking that way, are you thinking from power or are you thinking from fear? You're thinking from fear, right?  So it's easy to go to fear because that's what your brain automatically does. That is what kept our species alive. Our brain is designed to do one thing really well and that's help you survive. The problem with that is that it will usually go the easiest route, not pushing yourself, not doing things that you've never done before, not stepping into the unknown. So our brain is designed to keep us alive. We still have a part of our brain that's been around for 1.5 to 2 million years called the amygdala, which is where all fear comes from. The fear of oh my gosh, I don't know if I'm going to be attacked by a lion when I walk outside has now been turned into the fear of what if I fail? What if I'm judged? What if I get rejected by people? What if people throw their opinions at me? And so now because we don't have the fear of death, we now have the fear of judgments and rejections and opinions because the amygdala still exists. So most people, what your brain is going to automatically do, pretty much everybody, what your brain is automatically going to do is go to a place of fear. And so we have to consciously be aware of this and have ourselves step out of the fear and into our own personal power. And when I say power, I don't mean power in controlling other people because people can think, you know, it can have a bad connotation of power. But when I say power, I mean power is you stepping into who you could be, being coming from an actual powerful place, being a powerful being in this world. And so that's why it's very important to be self aware is because if you're not self aware, if you're not paying attention to where your brain's doing, what your thoughts doing, what your actions are doing is a majority of time will actually sink into fear, will sink into comfort, will seek into coiling away instead of actually stepping out and doing what it is that we want to do.  And I don't mean fear of death, like I'm not going to drive 200 miles an hour because of the fact that I could die at 200 miles an hour, lose control of my car.  Probably none, right? But if you look back, ask yourself how many of your decisions that you don't love or that you wish you would have done differently came from a place of fear where you're like, man, I feel like I wasn't as good as I could have been. I feel like I didn't step out. I feel like I didn't bring what I could to the world. How many of those decisions came from a place of fear? Usually it's most of them, right? If you think about all of the great decisions that have been made in the world, all of the amazing things that have happened in the world, all of the amazing companies that have been built, all of the amazing products that have been built, the biggest inventions in the world, how many of those came from a place of fear? Probably none. Why? Because nothing is really built, nothing amazing is built, nothing inspiring is built on fear, no life that becomes amazing is built on fear, which goes into if you think about the people that you are inspired by the most, the Steve Jobs, Elon Musk's, Michael Jordan's, whoever they might be, whoever it is that inspires you, Gandhi, Nelson Mandela, how many of them live the life filled with fear and made decisions based in fear? None of them, the people that you look up to, the people that have the most inspiring stories are always the people that step into their own personal power. They know that there's probably going to be people against them, but they know what they're worth, they know what they're supposed to do, they know where they're going in this world, they know what they're building, and they know that there might be resistance, but they're not going to let fear control them. What are they going to do? They're going to step into their personal power and they're going to make decisions based on that personal power. Now you can start to see the importance of realizing when you're coiling away in fear and when you're actually stepping up into a place of personal power. An example of a decision that's important that people need to be made is, like I told you earlier, starting a business. Most people go the quote unquote safe route by working for another company. We all learned in 2020 that the safe route is not safe because immediately 35 million people lost their jobs. So what was safe? They actually rise is completely unsafe. What's the safest job you can have? Working for yourself. Why?  That's safe if you ask me because companies could just change their mind and you're gone the next day. But how many people coil away and stay at a job that they don't enjoy or that they weren't meant for or that's not fully fulfilling to them and don't go and do what they truly want or don't start a business or don't start a nonprofit simply because there happens to be fear because they're not stepping into their own personal power. Think about that for a second. Another thing that pops into my head as well is investing, right? So investing, let's say it's investing into the stock market, right? How many great, great stock market decisions came from a place of fear? Probably not too many. How many great decisions into investing into companies came from a place of fear? Probably not too many. Usually it's personal power. What about investing into your own personal vomit? Maybe you want to learn how to do something and there's a course or a seminar or a person that you can hire to be your mentor, right? You could go, oh man, I don't know about spending this money. I don't know if this person's worth it. I don't know if I'm going to make my money back. I don't know if this is truly what I meant to do. Then you can have all those fearful ideas and thoughts come into your head and you can listen to those and stay in the exact same place and not invest into yourself or you can say, you know what, this is what I truly want to do. I'm going to pay this person to help me figure it out or to teach me or to build the course or whatever it is that I need to do to help me build my business, to help me build my relationship, to help me build my finances, whatever it is.  I do want to take control of my finances. So I will hire this financial advisor or finance coach or whatever it is that you're hiring and go, I'm going to step into my personal power right now and learn from this person. So there's two examples right there of fear decisions. You could go into fear or you could go, I'm going to take control of my life. This is what I truly need to do. This is what I want to do.  Because there was no risk. You're like, I'm going to take the less risky way. Probably not many. There's a quote that says in life, if you don't risk anything, you risk everything. Let me say that again. In life, if you don't risk anything, you risk everything. And so how long have you been sitting in a place of taking as little risk as possible, taking the easy route because you're afraid of what could happen if you stepped off into your own personal power? How many life changing decisions could you have made in your life?  How many moments of decision did you have that you decided to play safe instead of deciding to step up into your own personal power? When you know that you should have, think about that. And usually, the difference is that your gut feeling knows that you need to step into your own personal power. Your gut feeling, I always call your emotional compass. So it's kind of like you're guiding light and you're following this thing that you want to be doing, not even that you want to be doing, that you feel like you're supposed to do. And your gut feeling will give you the intuition, the intuitive hits to say, Hey, this is the path you're supposed to go down. And we can feel this path of like, I want to go start my business. This is what I'm supposed to do. But we can listen to our brain because our brain is always filled with fear and say, Oh, but that doesn't make sense. You're not going to make any money doing this. You have a family you have to support.  What if you don't succeed? What if you and your family are homeless? And so there's always the gut feeling, which is usually the personal power.   And so when you think about it, when you feel those feelings of, Oh my God, I don't know if I should do this or not, you know that when you feel that fear coming up that you're on the edge of your comfort zone. And what do you do when you're on the edge of your comfort zone? Lean in because it's showing you that this is a place to grow. This isn't a place to coil away. This isn't a place to step back. This isn't a place to get to, to go in the opposite direction. If I'm feeling those feelings of fear, that's a good thing. That's showing me, Rob, you're at the place now where you're about to grow. And if you want to get to the next level, the next iteration of who Rob is, you're going to have to lean into this fear. People still feel the, and I say this all the time is that successful people still feel fear. The difference is they don't listen to it. Unsuccessful people also feel fear, but the problem is they listen to it and then they coil away and they stay in their comfort zone, become afraid. I hope that next time you feel that fear pop up, you go, Nope, I'm going to do this.  It's about what you, it's about stepping into what you could be, what you should be versus what you are. Right? You know where you are. You know what happens when you do exactly what you've done. And if you think about it, and the question I was left to ask is, how long have you been stuck in your current comfort zone? Six months a year, two years, three years, five years, 10 years, 20 years, maybe, if you continue to do the same things and continue to coil away every time you feel this big moment of decision and step into a place of fear, then if you fast forward 10 years from now, you're going to be in the exact same position. I promise you that, but if you were to go, you know what, I'm going to, I feel the fear. And when I feel the fear, I know that I have a decision of either going with the fear or going with personal power. What does my gut say that I should do? My gut's telling me to move forward instead of coil away. Okay, that scares the out of me, but I'm going to do it anyways. And then if you do that over and over and over again and step in and lean into the fear, guess what happens? You fast forward five years from now, 10 years from now, you have a completely different life, completely different. But that's the difference is you need to become very self-aware of what's actually happening. And when you're starting to coil back and be afraid and take a step back versus actually leaning in to the discomfort. So you've got to be very self-aware of when you're feeling those. And the thing about is noticing fear is a good thing. Like I said, because, well, here's the first thing, noticing the fear is a good thing. Listening to the fear is a bad thing. So if I notice fear, number one, that's good because I'm becoming self-aware when before I was probably just, just reacting to my fear and just following it subconsciously. So if I'm noticing my fear, that's a good thing because I'm becoming self-aware. Number two, as I said, it's showing me the edge of my comfort zone. So when I feel the physical feelings of fear, and you know the physical feelings of fear of like, Oh, I don't know if I should be doing this. I don't know if this is right. I don't feel good. This is making me very uncomfortable. Boom. I'm in a great place. I need to lean into that fear because if I lean into it, I'm going to be pushing myself out of my comfort zone. And each one of us should be putting ourselves, putting ourselves outside of our comfort zone at least once a day. And if you do this over and over and over and over again and push yourself out of your comfort zone and step into your personal power every single day and you fast forward five years from now, like I said, completely different life, but you have to realize the only person that can make that awareness of fear or personal power is you. And the only person that can make the decision of following your fear and listening to it or stepping into your personal power is you. So if you continue to listen to your fear and you fast forward five years from now, you're not going to like where you are. I promise you that if you continue to listen to your fear and you fast forward five years from now, listening to your fear, you're not going to like where your life is at. But if you notice your fear and go, okay, I'm aware of my fear. Now that's telling me I need to find what my personal power is and what I need to step into and what my gut is telling me to do. So I'm going to step into that fear. I'm sorry, step into that, that personal power because I feel the fear and you do that every single day consistently knowing that you're not going to die when you step into your personal power. You'll have a completely different life in five years. But if you listen to it, listen to that fear and stay in the fear, you're not going to like where you are. So the goal is to notice the physical feelings, notice the thoughts that are happening inside of your brain and then become very self-aware. When you take yourself out of the jar and read the label, you know, when you're in the jar, you can't read the label.  They are. Are they about to make it? So there's two decisions. There's a fearful decision and there's a personal power decision. You write it down on piece of paper. Which one should they take as if it's not you and you're coaching this person? Okay, the fear decision is this. What's going to happen? What are the repercussions if they follow this fear decision? What is their life going to look like in five years? Okay, what is the repercussions if they decide to step out of their comfort zone and follow their personal power? Where could that take them in five years? And when you actually start to plan it out, you become self-aware and you start to decide, you know what? I'm going to start to make the majority of my decisions coming from a place of personal power instead of a place of fear. And you do this every single day, promise you, you will wake up five or 10 years from now and have a completely different life that is completely unrecognizable to the person that you are right now. But as I always say, there's only one person that can make that decision for your life and that is you. So either step into fear or step into personal power. The choice is yours.