Photorefractive Mutually-Pumped Phase Conjugation with Coherent Beams: Sensitivity to Small Perturbations

Mutually-pumped phase conjugation in BaTiO₃ crystal with two coherent incident beams has been studied experimentally for the bridge configuration. We observed that when the two pump beams are blocked individually, the transient behavior of the phase conjugation reflectivity with coherent beams was greatly different from that with incoherent beams. The phase conjugate reflectivity was sensitive to small perturbations such as vibration, exhibiting a change of as much as a factor of 10. The response time to the vibration was measured to be about 0.3s.