Abstract

In experiments with a cw 1.0 … 2.0-W Nd:YAG laser beam modulated by a chopper (pulse duration 0.6 … 6.0 ms, a pulse repetition rate 60 … 600 ms) and focused into a nematic liquid crystal (NLC) layer 2 mm thick (with absorption at 1.06 μm about 0.4 ms and with the homeotropic orientation achieved by an ac electric field), lasing of the backscattered signal was observed. This effect was registered both in experiments with a single pump beam in the NLC cell with a mirror-reflecting wall and in experiments with two independent pump beams in a NLC cell with transparent walls (Fig. 1). The temperature dependence of the delay time of the generated signal, changing from 500 to 100 μs and the decrement of the threshold power with temperature increase have shown the thermal nature of the parametric generation.

© 1992 Optical Society of America