Optical guided mode studies of the director structure in FLC cells

Abstract

The optical excitation of guided modes has been used to characterise in detail the director profile in a range of Ferroelectric Liquid Crystal cell structures. There are a variety of possible cell geometries which may be used. Most of these are not particularly suitable for the study of real commercial cells. In this study we review the earlier techniques and go on to show results from the recently developed Half Leaky technique may be fitted using a genetic algorithm approach. A further development in this are, the Fully Leaky guided wave technique using low index coupling prisms and a real commercial ceil is also briefly discussed. This new procedure involving monitoring both reflected and transmitted signals and combined with the genetic algorithm fitting routine paves the way for detailed studies of commercial devices.