Stationary Self-Trapping of Optical Beams in Dense Media with Lorentz Local-Field Corrections

Abstract

We describe a method for finding expressions for nonlinear electrical susceptibilities of dense media which are "exact" to all orders of the field strength, in the context of the Lorentz local-field theory. The method requires as a starting point the corresponding susceptibility to all orders for a dilute gas. We apply this method to determine the nonlinear susceptibilities responsible for self-trapping of optical beams in C${\mathrm{S}}_2$ and ${\mathrm{C}}_6$ ${\mathrm{H}}_6$. A graphical method for finding approximate filament sizes from the susceptibility curve is described, and the self-trapping equation is solved numerically. Our results for the susceptibility and for the filament sizes differ, in the low-power region, from previous work. We find smaller filaments containing less power.