Transfer of temporal fluctuations in photorefractive two-beam coupling

Transfer of temporal fluctuations between the signal and pump beams in diffusion dominated photorefractive two-beam coupling is studied experimentally. The dependence on the gain, beam intensity ratio, and frequency of the fluctuations is found to agree well with a linearized analysis, The transfer of perturbations is frequency dependent at low frequencies, and becomes constant at frequencies large compared to the inverse material time constant. Vde discuss the possibility of pump noise suppression when amplifying weak signals. (C) 1997 American Institute of Physics.