Optical studies of low-birefringence liquid crystal solutions using a multi-wavelength hollow prism refractometer

This article presents the study of low-birefringence liquid crystal solution using the multi-wavelength hollow prism refractometer. Phase transition temperatures are measured with Fabry-Perot scattering spectroscopy and an optical polarization microscope. The ordinary and extraordinary refractive indices for two different liquid crystal solutions are measured at three different visible wavelengths and at various temperatures using a hollow prism refractometer. The empirical Cauchy formula is used to investigate the dependence of refractive indices on wavelength. The thermal dependence of the refractive indices is investigated by means of the modified four-parameter model. The values of Cauchy's constants, material constant, thermal variation of birefringence, order parameter, and constants involved in the thermal variation of average refractive index are computed for later application and use. The calculated values for the constants were verified using the experimentally observed values. The anisotropy in the polarizability values of the solution is responsible for the strong temperature dependence of the birefringence, order parameter value, and declining order in the system with the increasing temperature.