Characterization of Temperature-Dependent Refractive Indices for Nematic Liquid Crystal Employing a Microfiber-Assisted Mach–Zehnder Interferometer

The temperature dependence of refractive indices for nematic liquid crystal (NLC) is characterized in the near-infrared region by employing an all-fiber ultrasensitive microfiber-assisted Mach-Zehnder interferometer (MAMZI). Owing to the unique thermal-optic properties of NLC, the proposed MZI shows inverse temperature sensitivities of -7.311 and 77 nm/K right above and below the clearing temperature of liquid crystal E7, respectively. Furthermore, the temperature dependences of ordinary and extraordinary refractive indices could be acquired by performing curve fitting on the experimentally measured interference dip wavelength as functions of environmental temperature based on the four-parameter model derived from Vuks equation.