Determination of Refractive Index and Birefringence of Nanoparticle-Doped Liquid Crystals

The purpose of this article is to investigate the effect of adding nanoparticles on the birefringence of nanoparticle-doped liquid crystals. The approach of this study is based on an analysis of liquid crystals doped with two different types of nanoparticles, viz Fe2O3 and ZnO. The wavelength and temperature-dependent behaviour of the nanoparticle-doped liquid crystal solution were investigated to obtain ordinary, extraordinary and average refractive indices. The paper also presents a comparative study of the indices of refraction, birefringence, order parameter and molecular polarizabilities of the samples obtained experimentally and using the theoretical model. The results indicate that the properties of the sample doped with nanoparticles show an improvement in the birefringence and polarizability ratio value with varying temperatures. 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. Samples of liquid crystals doped with Fe2O3 nanoparticles showed a higher increase in birefringence than samples doped with ZnO at all temperatures, suggesting strong molecular interactions and greater applicability. The observed result may be attributed to the stabilization of liquid crystal matrix due to the presence of nanoparticles in the molecules.