Optical distortion in nonlinear phase conjugation by three-wave mixing

Abstract

The phase and amplitude of a conjugate wave front generated by three-wave mixing in a lithium formate crystal were examined experimentally using a polarization shearing interferometer and a silicon diode array. It was found that the phase of the conjugate wave front had little distortion, while its amplitude was modulated significantly. The distortion is due to interference of conjugate waves generated from different positions in the crystal and not due to failure to satisfy the phase-matching requirement. A theoretical description is presented that is in good agreement with observation.