In astronomy, the angular size of a source can be detected by one of these things designed by Hanbury, Brown, and Twiss. The Jamin type of these devices is used to measure the refractive index of gases. The cavity for lasers is often used created using one of these things called an etalon, though it's alternately named Fabry and Perot. LIGO searches for (*) gravitational waves by using two of these devices. Another of these devices failed to produce a fringe-shift, which was inconsistent with the presence of a luminiferous ether. That device was designed for the Michelson-Morley experiment. For 10 points, name these devices that split a beam of light, create a phase 
In astronomy, the angular size of a source can be detected by one of these things designed by Hanbury, Brown, and Twiss. The Jamin type of these devices is used to measure the refractive index of gases. The cavity for lasers is often used created using one of these things called an etalon, though it's alternately named Fabry and Perot. LIGO searches for (*) gravitational waves by using two of these devices. Another of these devices failed to produce a fringe-shift, which was inconsistent with the presence of a luminiferous ether. That device was designed for the Michelson-Morley experiment. For 10 points, name these devices that split a beam of light, create a phase shift, and recombine the beam to create a namesake pattern.
In astronomy, the angular size of a source can be detected by one of these things designed by Hanbury, Brown, and Twiss.
interferometers