Abstract

We consider the classical and quantum mechanical processes of three wave interaction [including second harmonic generation (SHG) as the degenerate cast] in nonlinear χ⁽²⁾ crystals where all three waves are excited from the beginning. Using coherent initial states (but also squeezed, Kerr and other states) an arbitrary initial phase difference can be adjusted. Then, in general, each amplitude and each phase of the signal, idler and pump can change and so the phase difference. This has passed unnoticed up to now because usually (at least) one wave starts in the vacuum and adjusts automatically the right phase which stays constant.

© 1996 IEEE