Threshold behavior and electro-optical properties of twisted nematic layers with weak anchoring in the tilt and twist angle

Analytical and numerical calculations of threshold behavior and electro-optical characteristics in twisted chiral nematic layers are presented, when weak anchoring in the tilt and twist angle of the director is assumed. An analytical expression for the effective twist angle and the Freedericksz threshold voltage is derived. In cells with bistabilities, we investigate the influence of the anchoring parameters and device parameters on the width of the hysteresis. Using the 4X4-matrix formalism of Berreman [J. Opt. Soc. Am. 62, 502 (1972)], we demonstrate the influence of the weak anchoring on the transmission-versus-voltage characteristic

Interferences with a Plane Parallel Plate Near the Critical Angle of Total Reflection

The fringes of equal inclination with a plane parallel plate surrounded by an optically denser medium start at an angle of incidence less than the critical angle of total reflection. Despite its practical importance this effect was disregarded in optics up to now.</jats:p