Optical Flickering Effect and Director Fluctuation in Nematic Liquid Crystals studied by Total Reflection Spectroellipsometry

Abstract

Optical flickering effect in a nematic ECB cell under a bipolar electric field has been studied by total reflection time-resolved spectroellipsometry (TRSE). The origin of flickering effect is discussed in terms of a change in internal electric field and thereby induced director fluctuations. The flickering effect can be compensated and may change its sign when a bias electric field is applied. Moreover, the director decay shows a strong frequency dependence. It is also shown that the essential feature of the observed flickering effect can be reproduced by a simulation that assumes ion migration and director reorientation.