Calulation of gaussian-wavefront variations induced by a photorefractive grating with ono-90 phase shift

Variations in the amplitude and phase distributions of an incident Gaussian beam are derived analytically when it propagates through a photorefractive crystal in the presence of another strong beam and resulting photorefractive grating that is phase shifted by other than 90.deg. relative to the intensity grating. In the presence of the photorefractive grating the beam is shown to propagate along a straight line in a new direction with an increased wave number.