Optical Bistability in a Photorefractive Self-Pumped Phase-Conjugator.

We demonstrate the bistable behavior in a photorefractive self-pumped phase-conjugator (SPPC) theoretically and experimentally. In the method, an incoherent erase beam is used to erase the four-wave mixing (FWM) region of the SPPC, and thus the threshold of the SPPC depends on the intensity ratio of the erase beam to the sum of the coherent beams in the FWM region. Even a white light can be used to control the reflectivity as a switch.