Abstract
In this paper, another approach to measure the refractive indices of liquids is proposed. The method is based on lens-fibre interference. This uses a capillary tube containing the measured liquid instead of the fibres. A part of the capillary tube is empty to calibrate the system. A simple mathematical expression has been derived to get the liquid refractive index by measuring only the deviation angle from the interferogram. The constants that relate the liquid refractive index to the deviation angle have been determined using a standard set of liquids. This method can measure liquids' refractive indices in a wide range with an error less than +/- 1 x 10(-3), which is expected in the case of two-beam interference.