Highly efficient lasing at difference frequencies in a nematic liquid crystal

Highly efficient lasing at difference frequencies is obtained in a nematic liquid crystal excited by several visible lines from a cw argon laser with a total power of 0.08—1.5 W. The maximum conversion efficiency was ≈1% and the quadratic susceptibility was ≈2×10-6 m V-1. The field of application of the approximate mechanism of quadratic nonlinearity and frequency conversion considered in the paper requires specification. The nonlinear conversion of radiation in a nematic crystal has specific features compared to lasing at difference frequencies in solid crystals.