Abstract

Most of the photorefractive nonlinear phenomena are based on the buildup of a spatial electric field grating by a pair of coherent light waves with equal or nearly equal frequencies. This grating consists of a fundamental component with grating vector K and a set of higher spatial harmonics. The fundamental grating is frequently described by Kuchtarev’s formulas connecting the space- charge field with the light-wave amplitudes.¹ Two methods for enhancing the space-charge field have been proposed which are based on the introduction of a frequency detuning Ω between the light beams² and on the application of an alternating ac field.³

© 1993 Optical Society of America