2-DIMENSIONAL PERTURBATIVE ANALYSIS OF SLANT GRATING IN PHOTOREFRACTIVE CRYSTALS IN AN EXTERNAL ELECTRIC-FIELD

A slant grating was recorded with two laser beams incident on photoref ractive crystal in an external de electric field. Two-dimensional pert urbative analytical solution for the first two-order space-charge fiel d for steady-state photorefractive slant grating recording has been ob tained. It is shown that the inclusion of the longitudinal component o f the space-charge field during photorefractive two-wave coupling can predict reduction of the fundamental harmonic and enhancement or reduc tion of the second-order harmonic for various applied field strength a nd various grating slant angles. The dependence of the first two-order harmonics on the slant angle and on the applied field strength is exa mined.