Low-Frequency Noise and Photoinduced Scattering in Photorefractive Crystals,
INSTITUTE OF AUTOMATION AND ELECTRICAL MEASUREMENTS NOVOSIBIRSK (USSR)
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Photoinduced scattering PS is inherent in a varying degree in any photorefractive crystal. The origin of the PS is quite clear this is an amplification of the weak seed scattering. A number of papers, deal with a description of the effect. The pump and scattered waves supposed usually to have the same frequency. In the framework of that approach, a steady-state PS may only be caused by the nonlocal photorefractive response i.e. by shifted gratings. However, in many cases experiments show the steady-state PS to be abnormally large and this can not be accounted for by the nonlocal response. LiNbO 3 Fe crystals, where the local response i.e. unshifted gratings exceed in value the nonlocal one by 10 1-10 2 times, can be pointed out as an example. We suggest a new interpretation of the PS for crystals with a predominant local response.