Surface- and optical-field-induced Freedericksz transitions and hysteresis in a nematic cell

For a homeotropic nematic liquid-crystal cell, this paper explores the influence of the surface anchoring and the cell thickness on the first-order optically induced Freedericksz transitions. The exact criteria for the existence of the first-order transitions at the threshold and at the saturation, respectively, are obtained in terms of material and device parameters for arbitrary anchoring conditions. The critical cell thickness, when thinner than which the first-order transitions will exist, is obtained. A standard for estimating the strength of the first-order transitions is proposed. The group equations for determining the tricritical points are listed. The factors, especially the nonmaterial factors to enhance the first-order transitions are discussed at length.