don@allegra.UUCP (D. Mitchell) (03/29/84)
Stimulated emission can ONLY happen with bosons. In fact, physicists say photons obey "Bose-Einstein" statistics because Einstein first explained stimulated and spontaneous emission (the famous "A" and "B" coefficients). Only with Bosons do you get the situation that the probability of stimulated emission (of a photon is a certain state) will be proportional to the number of photons (all in that certain state) comming by the excited atom. Also, when the atom emits, the photon it gives off will be in the SAME STATE as the big herd of photons coming by; that is, it will be the same frequency and direction and will be in phase with them. That is why laser light is coherent.