Tuesday, 30 January 2018

statistical mechanics - Can one stimulate emission of a photon with an energy different from the emitted photon?


Suppose I have a three-level system with E0 the ground level, E1 the intermediate and E2 the upper level. In thermal equilibrium they will have a certain probability distribution according to the Boltzmann Statistic, in a laser one needs a population inversion, but that doesn't matter for my question.


My question is this: 3-level laser uses the E1E0 transition because the E2 level decays quickly (by design), i.e., emission of an E1 photon is stimulated with an E1 photon. But is there also a stimulated emission of energy E1 for an incident photon of energy E2E1? My thinking is that a photon energy of E2E1 kicks the electron from E1 in the upper state E2, which will then decay, and every once in a while it should decay into the ground level, not back into the E1 state. Is that correct? And if that is so, is the momentum of the emitted photon with energy E2 aligned with the momentum of the incident photon of energy E2E1?




No comments:

Post a Comment

Understanding Stagnation point in pitot fluid

What is stagnation point in fluid mechanics. At the open end of the pitot tube the velocity of the fluid becomes zero.But that should result...