[Paper] Estimation of Flexoelectric Coefficients by Means of Transmission Phase Difference of Nematic Liquid Crystal Cells

Abstract

Improvement of the flexoelectric coefficients estimating procedure by means of the transmission phase difference measurement was demonstrated. It was found that the sign of the sum of two flexoelectric coefficients for splay and bend deformation can be determined from the DC applied voltage dependence curve of the phase difference for obliquely incident light. The value of the sum of two flexoelectric coefficient was evaluated by means of symmetric oblique incident transmission ellipsometry (SOITE), and the several pC/m are recognizable by numerical fitting. Subtraction of two flexoelectric coefficients was also estimated with normal incidence measurement under DC applied voltage. From these three step evaluations, two flexoelectric coefficient with accuracy of several pC/m was confirmed for seven of nematic liquid crystals.