Polarization multiwave mixing in saturable absorbers

摘要

This work presents experimental studies into the energy efficiency of multiwave mixing in complex molecular media exhibiting higher order nonlinearities in two cases: volume holograms in the standard geometry of degenerate four-wave mixing and self-diffraction of the recording waves from thin dynamic gratings. The use of different combinations of mutually aligning polarizations for interacting waves enables one to determine the contribution into the interaction efficiency of various dynamic gratings and nonlinearity mechanisms. The role of polarization gratings resultant from spatial modulation of the light-field polarization state on orthogonal polarization of the hologram recording waves is established. Comparisons between the contributions of the polarization and "normal" gratings recorded by identically polarized light beams into the process of multiwave mixing demonstrate that the ratio of these contributions is dependent on the intensity of interacting waves. By variations in the propagation direction of a reading wave a change from four- to six-, eight- and ten-wave mixing may be realized.