Abstract

Although the possibility of two-photon laser action^1,2 was first discussed over 25 years ago, it has been realized only under a very limited set of circumstances^3,4 and never under cw optical conditions. This is unfortunate because the two- photon laser has been predicted to display a number of interesting properties,^5,6 such as bistable operation, novel threshold behavior, and in some cases squeezing. This situation is primarily a consequence of the presence of competing one-photon processes that occur in the previously considered two-photon gain media.

© 1991 Optical Society of America