Abstract

In experiments which have been performed to date at the Naval Research Laboratory,¹ it has been discovered that the results can be characterized by the Fresnel number of the aberrations $D_A^2/\lambda L$, where D_A is the transverse scale length of the aberrations, L is the interaction length of the pump and Stokes beams, and λ is the pump wavelength. The results are characterized by the geometry (collinear or crossing beam) and aberrations (phase, amplitude, or both). We show that many of the experimentally observed effects can be explained by a linear theory, although nonlinear effects due to pump depletion are in most cases important. The circumstances in which off-angle contributions, copropagating with the crossing beams, are seeded by the pump and can grow to important levels are elucidated.

© 1987 Optical Society of America