Ultrafast active phase conjugation in broad-area semiconductor laser amplifiers

We predict and investigate ultrafast optical phase conjugation generated by the spatiospectral mixing of two picosecond light pulses in the active area of a broad-area laser. The microscopic internal processes linked to these phenomena are described on the basis of multiwave Maxwell-Bloch equations and include, in particular, the dynamic interactions of the counterpropagating light fields self-consistently with the dynamics of the active nonlinear charge-carrier plasma within the laser amplifier. Microscopic simulations demonstrate the spatiotemporal dynamics of the fields and reveal the underlying physical processes of the ultrafast refractive-index grating formation: dynamic spatiospectral hole burning, carrier heating, and coupled diffraction and interference of the light beams by means of the nonlinear induced changes in the spatiospectral carrier and refractive-index distribution. (C) 2001 Optical Society of America.