As in chiral nematic liquid crystals, one of the most striking optical properties of chiral smectic C liquid crystalline phases is the selective reflection of certain wavelengths of light. This Bragg-like scattering is a direct consequence of the periodic nature of the helical structure of these phases. In chiral nematics, the strong coupling of the light to the periodic structure leads to scattering in the dynamic (multiple-scattering) regime. In chiral smectic C phases, the strength of the coupling depends on the magnitude of the tilt angle between the long molecular axis and the layer normal. For small tilt angles, the kinematic (single-scattering) regime of light scattering occurs. Further, due to the nature of the modes of optical propagation in the chiral smectic C phase, some Bragg events occur as depolarized light scattering in the forward direction. A computer program has been written to calculate the light scattering from a chiral smectic C sample. The results of these calculations demonstrate the behavior of the light scattering in both the kinematic and dynamic regimes.
© 1978 Optical Society of America
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