Abstract

The nature of the first moment ensemble averages of the scattered light fields from an acousto-optic (AO) device in the Bragg regime under the influence of noise is investigated. We start from the wave equation in the presence of the AO interaction term and the noise fluctuation terms. Thereafter, we take the ensemble average and employ the Fourier transform technique to derive the transfer function of the diffracted light. The impulse response at the output can then be found by taking the inverse Fourier transform. The intensity profile at the output has coherent and incoherent contributions from the deterministic and random parts of the impulse response. The random part suggests that the Bragg-diffracted light beam intensity will be attenuated because of the optical imperfection of the AO medium. Furthermore, the light beam profile will be distorted because of the imperfections in the sound profile resulting from the bonding between the transducer and the AO device, random sound scatters, etc. We compute the dependence of the signal-to-noise ratio of the first order light on the mean square values of the distributions of the imperfections and scatters.

© 1992 Optical Society of America