Passive laser Q-switching using a dye-doped liquid-crystalline layer near total internal reflection

Abstract

The process of optical switching of a modulator based on nonlinear variation of the reflection coefficient at the “glass–dye-doped liquid-crystalline layer” interface near the critical angle of total internal reflection that occurs as the layer is heated with a pulsed solid-state laser radiation has been studied. Various switching modes based on reflection of the s- and p-polarized waves from either thin ( d∼ λ) or thick ( d≫ λ) absorbing LC layer have been investigated. Q-switching of a ruby laser by means of the LC modulator has been realized, and giant pulses of 1 J energy and 60 ns duration have been obtained. Changing the LC layer orientation director by a DC field enables to control laser operation mode and giant pulse parameters.