Fully leaky guided wave determination of the polar anchoring energy of a homogeneously aligned nematic liquid crystal

Optical excitation of a series of fully leaky guided modes has been used to explore the director distortion of a homogeneously aligned nematic liquid crystal (Merck-BDH E7) under application of an ac electric field (1 kHz) no rmal to the cell wall. Homogeneous alignment is realized by rubbed polyimid e films on glass plates with indium-tin-oxide coatings. By using continuum theory to model the director profile through the cell to fit the fully leak y guided mode reflectivity and transmissivity data, both with and without a pplied fields, the changes of surface tilt angle and its gradient can be ob tained from which the polar anchoring coefficient, W-theta, is derived. At 26.8 degrees C we find that W-theta = 1.2 x 10(-4) Jm(-2). (C) 2000 America n Institute of Physics. [S0021-8979(00)00306-6].