On the Theories of Optical Reflection from Cholesteric Liquid Crystal Films
One of the unique optical properties of cholesteric liquid crystals, viz., the optical reflection has been theoretically dealt by a number of workers, using two different models: one based on the Oseen’s dielectric continuum model; and the other by using the difference equations for wave propagation in a periodic structure (as in Darwin’s dynamical theory of X-ray diffraction). de Vries(1) and Aihara and Inaba(2) have used the first model to explain the optical reflection at normal incidence. Taupin(3); Berreman and Scheffer(4) have treated the case of oblique incidence and have calculated by numerical methods the reflected and transmitted intensities. Dreher, Meier and Saupe(5) have solved the case of reflection by cholesteric liquid crystals for arbitrary angles of incidence. Chandrasekhar and Srinivasa Rao(6) and Chandrasekhar and Shashidhara-Prasad(7) have discussed the reflection for normal incidence using the second model. In fact, both the approaches are shown to be fully equivalent by Nityananda Rajaram(8).
KeywordsOblique Incidence Optical Reflection Cholesteric Liquid Crystal Secondary Maximum Maximum Reflection
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- (3).Taupin, D., Journal de Physique., 30, c4–32 (1969).Google Scholar
- (6).Chandrasekhar, S. and Srinivasa Rao, K.N., Acta Cryst., A24., 445 (1968).Google Scholar
- (8).Nityananda Rajaram: ‘On the theory of propagation of light by cholesteric liquid crystals’ Mol. Cryst. and Mq. Cryst. (in press).Google Scholar
- (9).Fergason, J.L., ‘Iiquid Crystals’, Gordon and Breach, New York-Xondon-Paris, edited by Brown, G.H., Diennes, G.J. and Labes, M.M., p 89 (1967).Google Scholar
- (10).Shashidhara Prasad, J. and Madhava, M.S., s ‘Optical rotatory dispersion of cholesteric liquid crystals’ Mol. Cryst. and Liq. Cryst. (in press).Google Scholar
- (11).Shashidhara Prasad, J (Mysore University Journal 1973).Google Scholar