Chi Ching CHANG

Department of Applied Physics, Chung Cheng Institute of Technology, Tahsi, Taoyuan 335, Taiwan ROC

(Received March 17, 1997; Accepted July 10, 1997)

We demonstrate the simultaneous phase conjugation of multiple beams incident on the a face of a photorefractive barium titanate crystal. The input beam power, angle and position were set so that no phase conjugation occurs unless a switchable incoherent inducing beam is present on the ?c face of the crystal. The use of the inducing technique with two mutually pumped phase conjugations for four input beams, or one self-pumped and one mutually pumped phase conjugation for three input beams can be performed in a crystal. Unlike the setup of conventional phase conjugation, which requires more precise arrangements, the novel setup of the multi-beam induced phase conjugation is relatively relaxed. The mechanism responsible for our discovery is qualitatively explained, and possible applications are mentioned.

Key words : phase conjugation, self-pumped phase conjugation, mutually-pumped phase conjugation, multi-beam induced phase conjugation

*chichang@cc04.ccit.edu.tw