Ring instability of wave front of light beams with regular temporal modulation
Varnavskii O. P. , Zhukov N. N. , Zaskal'ko O. P., Kuz'min V. V.
A study has been made of those aspects of a time-varying, small-scale self-focusing of light beams which result from a regular temporal modulation of the beam intensity. In this case, the nonlinear excitation of acoustic waves with frequencies which are multiples of the light modulation frequency is suppressed, while the noisy waves are amplified as a result of the perturbation of the density of the medium by both heating and electrostriction. The result is the appearance of a ring structure in the angular distribution of the scattered light.