Measurement of the Verdet Constant in Difierent Mediums by Using Ellipsometry Technique

This experiment is designed to measure the Verdet constant V through Faraday Efiect rotation of a polarized laser beam as it passes through difierent mediums, Flint Glass and water, parallel to the magnetic fleld B. As the B varies, the plane of polarization rotates and the transmitted beam intensity is observed. The angle through which it rotates is proportional to B and the proportionality constant is the Verdet constant times the optical path length. That by using ellipsometric parameters of under study was obtained. These are used to determine the Verdet constant for each medium and compared with standard known values. The experimental results are in good agreement with the corresponding theoretical analysis. 1. INTRODUCTION The Verdet constant is an optical constant that describes the strength of the Faraday efiect for a particular material. The phenomenon of the Faraday efiect was flrst observed by Michael Faraday in 1845. He discovered the concrete evidence for the relationship between the major branches of optics, magnetism and atomic physics (1). He found out that when a block of glass is subjected to a strong magnetic fleld, it becomes optically active. The efiect occurs when the rotation of a linearly polarized wave passes through a thickness of a transparent medium. However, rotations of polarized light are not only limited to optically active materials, but also including some optically inactive materials exposed to high magnetic fleld. In magnetized medium the refractive indices for right- and left-handed circularly polarized light are difierent. This efiect manifests itself in a rotation of the plane of polarization of linearly polarized light. This observable fact is called magneto optic efiect. Magneto optic efiects are those efiects in which the optical properties of certain materials are afiected by applied magnetic flelds or the material's own magnetization. Magneto optic efiects occur in gases, liquids, and solids. In this work, we propose a new method for measurement of the Verdet Constant (2{4) in dif- ferent mediums by using ellipsometry techniques limited only by the transmittance of the optical components and polarization ratio. The ellipsometry system (5,6) has been studied by using the instrument to change the angle parameter of various materials, namely, Flint glass and water, when change magnetic fleld. The experimental values for wavelength of 635nm are measurement and to compare its value to a theoretical calculated value. 2. THEORY