Non-Intrusive Technique for Measuring Refractive Index of Clear and Transparent Liquids

We propose an optical technique for measuring refractive index of clear and transparent liquids. This technique senses change in refractive index of liquid by virtue of lateral displacement of a light beam that occurs due to refraction of the light beam after passing through the liquid medium. The transmitted light beam gradually looses its alignment with a photodetector as refractive index of the liquid changes. Experimental results have indicated that the proposed technique has the potential to measure refractive indexes with an accuracy of 10-4, and it has novelty of being a simple and non-intrusive one.