Measurement of the refractive index of liquid using laser beam displacement

A simple method for measuring the refractive index of liquid is presented. When a laser beam impinges obliquely on a rectangular cell filled with liquid and passes through the cell, the propagation axis of the transmitted beam is displaced from that of the incident beam. By measuring the displacement, we can determine the refractive index of the liquid. Beams of a He-Ne laser and a laser diode were used for measuring the refractive indices of pure water and some organic liquids.