Stochastic resonance and noise-enhanced transmission of spatial signals in optics: the case of scattering

The nonlinear effect of noise-enhanced signal transmission by means of stochastic resonance in optics is studied. We investigate this effect for the novel case of spatial signals or images. With a theoretical model involving a threshold nonlinearity we describe a mechanism whereby the transmission of an image can be improved by the addition of noise. We argue that such a nonlinear mechanism can operate in different types of Light scattering. With a stimulated Raman scattering experiment we verify the existence of a stochastic resonance effect in the transmission of a laser image; we show that maximal efficacy is obtained with the assistance of a speckle of sufficient intensity. The results extend the scope of stochastic resonance and can serve as a basis for further development of the effect in optics. (C) 1998 Optical Society of America [S0740-3224(98)00310-5] OCIS codes: 070.4340, 100.0100, 110.2970, 030.4280, 190.0190, 190.5650.