Abstract:In this paper, a novel method combining orthogonal polarization laser self-mixing interference is proposed. The method utilizes a rotating cuvette to measure the refractive index of liquids at different concentrations.The cuvette is filled with the liquid to be measured and rotated by a certain angle.The change in the number of interference fringes, caused by comparing an empty cuvette with a liquid-filled cuvette, is used to calculate the refractive index of the liquid. A four-fold logic subdivision algorithm is then used to improve measurement resolution. The experimental results show that for pure water, different concentrations of NaCl solutions, and glucose solutions, the average relative errors are 0.47%, 0.59%, and 2.17%, respectively, with the maximum relative error within ±2.54%. The relative standard deviation of all solutions is less than 2%.