Refractive indices of liquid crystal E7 depending on temperature and wavelengths

The dependence of refractive indices of liquid crystal (LC) on temperature is represented by the Haller approximation model, and its dependence on the wavelength is expressed by the extended Cauchy model. We derived the refractive indices expressions of nematic LC E7 depending on temperature and wavelength simultaneously by combining these two models. Based on the obtained expressions, one can acquire the refractive indices of E7 at arbitrary temperature and wavelengths. The birefringence, variation rate of refractive indices, macroscopic order parameter Q, and orientational order parameter ⟨P2⟩ of E7 were then discussed based on the expressions.