Nonlinear processes in the formation of dynamic volume holographic gratings

The solutions of wave equations are used to develop new ideas on the dynamics of the diffraction efficiency of a volume light-induced grating in a medium with a nonlinear refractive index and/or absorption coefficient. It is shown that the earlier solutions have failed to describe satisfactorily the diffraction of radiation by volume phase and amplitude gratings because of distortion of the amplitude–phase profile of the radiation forming the grating. An analysis is made of the influence of the radial distribution of the intensity of the grating-forming beams on the observed changes in the diffraction efficiency. Predictions are made and experimental evidence is provided of the role of nonlinear refraction of a beam as a whole, which is an important factor in the space-time dynamics of the diffracted radiation in the far-field zone.