Homodyne and Heterodyne Problems in Measuring Spectral Width of Polarized Rayleigh Line Scattered by Nematic Liquid Crystals

To clarify the stray light effect in a polarized component which contains information about the splay viscosity coefficient, Rayleigh scattering from a nematic, MBBA, is observed at a small scattering angle α'=8° by a highly accurate microcomputer-based photon correlation spectrometer. By tilting a homeotropically aligned cell with respect to the incident light around the axis perpendicular to the scattering plane, the superposition of homodyne and heterodyne signals is confirmed at -3°≤φ'≤8°, where φ' is the azimuthal angle specifying the director. However, almost ideal homodyne detection is found to be possible unless φ'≈α'/2.