be applied by introducing a temporal phase shift in one of the beams in a two-wave mixing
configuration. The analysis of the Kukhtarev equations is based on the small modulation
approximation, but in contrast to earlier papers, no a priori approximations are made. The
analysis results in a second-order model with an explicit dependence on both the grating
spacing and the temporal grating frequency. Curves for the modulus and the imaginary part …