Refractometry of liquid samples with spectrally resolved white light interferometry

An interferometric method is presented to measure the differential refractive index Delta n of a liquid solution. The procedure is based on the spectroscopic analysis of the phase of a light beam which travels through the sample. The interferogram is recorded by a linear array of CCD photodiodes. The analogue signal so obtained is automatically processed by a microcomputer in order to get the refractive index. Precision of 2*10^-7 in Delta n is obtained. Experimental examples and alternative methods of data processing are presented.