Determination of Nematic Liquid Crystal Elastic and Dielectric Constants from Birefringence Experiments

A non-linear least squares technique was used to determine k 11, k 33, ε1 and ε2 by comparing data from a single birefringence vs. voltage experiment. Liquid crystal optical cells with parallel orientation were used to generate the birefringence-voltage curve from which the parameters were determined. Cell thickness was found to have a strong influence on parameter estimates which could not be accounted for in terms of the physical model used. In spite of the thickness dependence, the four parameters mentioned above could be estimated to a high degree of precision using techniques described herein.