Researchers Report Evidence for Lasing Without Inversion
SEP 01, 1995
A recent experiment may have achieved what many others have sought: a new way of lasing that avoids the need to pump many more atoms to a higher state than remain in the ground level.
DOI: 10.1063/1.2808154
We have come to think that lasing requires an inversion of population between atoms in an excited state and those in a lower state: Normally the probability of absorption from the lower state equals the probability of emission from the higher state, so that the only way to have more photons coming out than going in is to start with more atoms in the upper state. It would be useful to decouple the probabilities of emission and absorption, so that one could lower the loss associated with absorption without reducing the emission.
© 1995. American Institute of Physics
