<title>Z-scan measurements of optical nonlinearities in nematic liquid crystals</title>

Abstract

In order to study third order optical nonlinearities of nematic liquid crystals on the nanosecond timescale, we have carried out Z-scan measurements using a Q-switched Nd:YAG laser at 532 nm. The nonlinear refractive indices and absorption coefficients were determined for a number of liquid crystals at different temperatures. For the cyano-biphenyl 5CB, we used a two-pulse technique to estimate the response time, and we studied the intensity and wavelength dependence of the response to determine the dominant contributing mechanism. The correlation between the observed nonlinearities and the molecular structures is discussed.