Method and system for measuring Kerr rotation of magneto-optical medium

Abstract

First and second linearly polarized beams of light are incident on a magneto-optical disc at a common point. Both beams have equal or nearly equal intensity. Upon specular reflection from the disc, the first and second reflected beams travel through analyzers which are the same linear polarizers which originally polarized the second and first beams, respectively. The polarizers have an orientation such that the polarization angle between the first beam and the first polarizer is the same as the polarization angle between the second beam and the second polarizer. Consequently, the difference between the intensities of the two analyzed beams is proportional to Kerr rotation and independent of the direction of the stress axes of the magneto-optical disc substrate, and only mildly dependent on the magnitude of the retardation of the substrate.

Dependencies are inferred from the claim text.