A new simple analytical approach to degenerate four-wave mixing

Peter Bengtsson

Paul Michael Petersen, Per Michael Johansen

A simple analytic theory for degenerate four-wave mixing in photorefractive media is presented. The theory is valid when the backward pump-beam intensity is much smaller than the forward pump-beam and probe-beam intensities.

Z. A. Tagiev, Rena J. Kasumova, R. A. Salmanova

François Sanchez

A systematic study of degenerate two-wave mixing in the stationary regime in thin nonlinear local-response media is presented. The model is based on the coherent interaction of four waves, the two incident beams, and the two main diffracted waves. Analytical results are obtained in all cases investigated under the assumption of weak-beam amplification. It is demonstrated that the energy transfer arises only from the forward degenerate four-wave mixing terms. In particular, the theoretical results show two new features: (1) the gain factor of the interaction is substantially reduced because of the phase change associated with the two-wave mixing terms and (2) a phase mismatch can compensate for this phase change, leading to an appreciable gain enhancement. Moreover, the general case is solved numerically. Particular attention is given to the influence of separate two-wave and forward degenerate four-wave mixing terms. Self-diffraction effects and the gain dependence versus the ratio of the pump-beam intensity to the signal-beam intensity are investigated.

M. Dagenais

José Luis Paz, M.C. Bessega, A. J. Hernández