Accurate optical determination of liquid crystal tilt angle by the half-leaky guided mode technique

The first resonant guided mode of P --> P reflection in Half-leaky Guided M ode (HLGM) technique is very sensitive to the tilt angle of uniaxial liquid crystals. A formula is presented to describe the relationship between the tilt angle and the incident angle of the first resonant valley point of P - -> P reflectivity, R-pp. This method is suitable to measure tilt angle of a ny degree, especially 3-85 degrees, with high sensitivity. The great variat ions of LC layer thickness, LC near-surface sublayers, PI layers, or ITO la yers have few effects on the position of the first resonant valley point of R-pp. The method can be used to measure tilt angles with high sensitivity, without other influences, and exempt from the time consuming numerical fit ting with a complex model, which is needed in other methods by Guided Modes . (C) 2000 Elsevier Science B.V. All rights reserved.