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 Mode (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, Rpp. This method is suitable to measure tilt angle of any degree, especially 385, with high sensitivity. The great variations of LC layer thickness, LC near-surface sublayers, PI layers, or ITO layers have few effects on the position of the first resonant valley point of Rpp. The method can be used to measure tilt angles with high sensitivity, without other influences, and exempt from the time consuming numerical fitting with a complex model, which is needed in other methods by Guided Modes.
liquid crystal tilt angle half-leaky guided mode