Nonlinear effects in generation of optical and acoustic phonons by infrared resonance radiation

An analysis is made of the possibility of observation of nonlinear optical resonance effects in the lattice absorption range of crystals. Results are derived from the theory of nonlinear interaction of strong resonance radiation with dipole-active lattice vibrations, resulting in the appearance of nonequilibrium optical and acoustic phonons. Steady-state saturation of the lattice absorption and generation of acoustic phonons, occurring at infrared resonance field intensities of the order of 10³ W/cm², are considered. It is shown that these effects can conveniently be detected experimentally by active spectroscopy of light scattering.