Nonlinearity of the photorefractive response upon two-beam interaction in a bismuth silicon oxide crystal in an alternating electric field

Nonlinearity of the photorefractive response is studied experimentally and theoretically upon two-beam interaction of light waves in a bismuth silicat e crystal placed in an external meander electric field, The experimental da ta an shown to be in good agreement with a model, taking into account the i nfluence of the second harmonic of the space-charge field on a photorefract ive grating. The concentration of accepters in a crystal and a product of t he mobility of charge carriers by their recombination time are estimated fr om a comparison of the experimental and calculated data.