For 10 points, name this device that transforms various forms of energy into electromagnetic radiation.
The output of these objects is a solution to the paraxial form of the Helmholtz equation, and so can be modeled as a Gaussian beam. Einstein's A and B coefficients determine the efficiency of these devices. This device was preceded by a similar one using NH3 created by Gordon, Zeiger, and Townes. One technique used in these devices delays oscillation by modifying the (*) Q factor of the resonating cavity. A popular gas version of this device excites helium to a metastable state, which then transfer energy to neon to form an inverted population. The first one of these devices was created by Theodore H. Maiman using a ruby crystal. For 10 points, name this device that transforms various forms of energy into electromagnetic radiation.
The output of these objects is a solution to the paraxial form of the Helmholtz equation, and so can be modeled as a Gaussian beam.
lasers [or light amplification by stimulated emission of radiation]