CHARACTERIZATION OF NEMATIC LIQUID-CRYSTALS FOR NONLINEAR OPTICAL APPLICATIONS

We present some new experiments on self-diffraction in nematic liquid crystals and an extended static theoretical description of this effect. Our model gives some new insights and improvements to calculations carried out before. Using these calculations it was, e.g., possible to determine elastic constants in a pure optic way. For the static and dynamic measurements we designed a computer-controlled optical setup. It allows determination of the most interesting nonlinear optical properties of liquid crystals under variation of many parameters. The layout even allows application for any other nonlinear material. Especially modulation sensitivity, modulation transfer function and distribution of noise measured with just one setup are interesting for later application in optical signal or image processing. Furthermore, we present measurements one some new commercial nematic mixtures which show promising behaviour for future application in nonlinear optics. It was possible to verify our theoretical model with the experimental results. © 1990 Springer-Verlag.