Abstract

The counter-propagation of strong light beams in nonlinear media is capable of demonstrating a big variety of instability effects, namely, patterns formation, filamentation, temporal modulation instability, etc. Resonant media due to their spectral-selective properties enrich a nonlinear light behavior. For example, at copropagation of light beam with frequency of the blue side of a resonant transition, an emission with a frequency on the red side appears, forming a far-field ring structure. This conical emission displays itself as a frequency-shifted four-photon instability of the pump field, forming a set of stable filaments as a result of self-focusing.^1,2

© 1994 IEEE