Offset of Multiple-Beam Interference inside Anisotropic Multilayered Structure: Determination of Polar Anchoring Strength at Nematic Liquid Crystal-Wall Interface

An optical technique for eliminating the inaccuracy in the measurement of retardation caused by multiple-beam interference in anisotropic multilayer-structured thin film is developed by the detailed analysis of obliquely incident transmission ellipsometry. The director distribution of a nematic liquid crystal inside a conventional sandwich-type cell which constitutes glass substrates, alignment films and transparent electrodes can be accurately determined without taking complicated multilayer analysis into account. As a typical application, a novel method of determining of the polar anchoring strength at the nematic liquid crystal-wall interface is proposed. The accurate measurement of the director distortion of a NLC without information on the refractive indices of ITO films, alignment films and glass substrates results in the realization of polar anchoring strength with a high accuracy. This technique can be used to achive a strong polar anchoring reaching the order of 10-3 J/m2.