Optical properties of cholesteric materials used in surface stabilised cholesteric texture devices

N W Roberts, J P S Guillou, H F Gleeson, I Kirar, S J Watson, E O Arikainen

Research output: Contribution to journalArticle (Academic Journal)peer-review


An in depth study has been made of the optical properties of a series of non-thermochromic chiral nematic materials to determine the influence of refractive index dispersion on pitch measurements. The materials used were mixtures of a chiral nematic material, BL131a, and a nematic material 131,130 (from Merck Ltd.) in which the pitch is changed by varying the concentration of the nematic component. Detailed measurements were made of the ordinary and extraordinary refractive indices as a function of wavelength across the visible spectrum. Dispersion effects changed the birefringence by approximately 10% across the visible spectrum. Reflection. spectra were obtained and used to deduce the helicoidal pitch. Failure to include dispersion in the calculation led to a significant error in calculations of both the bandwidth and pitch of the material. Finally, as SSCT devices are electro-optic in nature, the influence of the conducting surface of the device on the optical properties is examined.

Original languageEnglish
Pages (from-to)1099-1111
Number of pages13
JournalMolecular crystals and liquid crystals
Publication statusPublished - 2004

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