MALUS' POLARIMETER (PC BASED POLARIMETER BASED ON MALUS' LAW)

摘要

A PC based Polarimeter is designed to measure the rotation of light based on Malus' law which states that I = 11 COs 2 8 where 11 is the intensity of linearly polarized light before the analyzer and I is the intensity after passing the analyzer and 8 is the angle between the plane of the vibration and the axis of analyzer. The said polarimeter comprising of a polarizer; and an analyzer (Glan Thompson prism) arranged on a common axis so that their transmission axes are parallel wherein when an unpolarized light is allowed to fall on the polarizer, the emerging beam is linearly polarized and its intensity is equal to half the intensity of incident unpolarized light, the said plane polarized light next passes through the analyzer and Since the transmission axis of the analyzer is parallel to this wave, it passes without any obstruction and its intensity I = 11. An optically active substance placed between the polarizer and analyzer which rotate the plane of vibration of linearly polarized beam that is passing through optically active substance; hence it is no more parallel to the transmission axis of analyzer but makes an angle of 8. The plane polarized monochromatic light, after passing through an optically active substance is being divided into two equal parts by using a beam splitter. One part of the light passes straightly through the analyzer, which is parallel to the Polarizer. The intensity after the analyzer (I) is measured, and 11 before the analyzer is always kept constant, thus, the optical