A polarimeter for the infrared region is described, which is used to measure the optical rotation due to the helical arrangement of molecules in cholesteric mesophases. The rotatory dispersion of mixtures of cholesteric liquid crystals and of liquid crystals in which the cholesteric structure is induced by a small amount of a chiral solute is discussed.
E. H. Korte and B. Schrader, "Measurement of the Infrared Rotatory Dispersion of Cholesteric Liquid Crystals," Appl. Spectrosc. 29, 389-393 (1975)