Two-wave mixing of phase-modulated beams in GaP under a dc electric field

Two-wave mixing of phase-modulated light beams in crystals of cubic symmetr y is analyzed on the basis of the vectorial theory of light diffraction. We derive an analytical expression for phase-to-intensity transformation in c rystals of the (4) over bar 3m point group of symmetry, which differs from the previously obtained solution based on the scalar approach. The most eff ective transformation is achieved when the amplitude of the space-charge-fi eld grating is equal to the quarter-wave field. It is shown that the space- charge-field grating created in GaP semi-insulating crystal at the waveleng th of 632 nm is much smaller than can be predicted from the one-level band- transport model. (C) 2001 Optical Society of America.