Infrared laser amplification and switching using nematic liquid crystal films

Abstract

Nematic liquid crystals possess sizable birefringence, good transparencies, and a large thermal refractive-index gradient in the visible as well as the IR regime. Using the orientational (Kerrlike) and thermal (diffusive-type) nonlinearities we show that large probe beam amplifications can be achieved with moderate power pump beam (with an intensity of the order of just a few W/cm2). The dependence of the experimentally observed beam amplification process on beam ratio, grating constant, intensity, film thickness, temperature, and frequency shift between the pump and probe has been measured and shown to be in good agreement with our detailed theories.