Dynamical theory of reflexion from cholesteric liquid crystals

Abstract

The analogy between the optical phenomena exhibited by cholesterics and the diffraction of x-rays from perfect crystals is empha- sized and some of its consequences are discussed. Difference equations similar to those formulated by Darwin in his dynamical theory lead to simple analytical expressions for the reflexion coefficient, rotatory power and circular dichroism which are shown to be in good agree- ment with the results of the rigorous electromagnetic treatment. An extension of the theory to absorbing systems at once yields the relevant formulae for the Borrmann effect in cholesterics. It is pointed out that this simple approach should be sufficient for most practical calculations.