Heterodyne detection of weak optical wavefronts burried in a photorefractive fanning noise

Abstract Weak signals, initially burried in the beam fanning noise of photorefractive amplifiers can be efficiently detected by combining the temporal filtering properties of coherent receivers with a spatial averaging over the random noise distribution that occurs from photorefractive effects. This is demonstrated by modulating in time the signal or the pump beam. Theoretical and experimental investigations using photorefractive BaTiO 3 in four different configurations are reported and compared.