Study of Magneto Optic Sensor Using Tdg Element

Abstract: The magneto optic sensor is very fast (at the speed of light), sensitive, non-contact and EMI (electromagnetic interference) proof in operation. It senses magnetic flux density by rotating the plane of polarization of the incident beam of light passing through it based on Faraday Effect. The amount of rotation depends on the property (Verdet Constant) of the magneto-optic element and the magnetic flux density. The general behaviour of this sensor is nonlinear. But under certain condition it shows linear nature over a certain range about an operating point which can be utilized in various applications. In this project this linear region of operation has been found and selected. The system can be used as an optical switch operated by current. Terbium Doped Glass cylinder is used in the experimental setup as the magneto optic element which is of length 30 mm, diameter 10 mm and with Verdet constant -104.42 rad/T m at the wavelength of 543 nm. The magnetic flux density is produced by passing the current through a solenoid.

Keywords: Polarization, TDG, Malu’s Law, Mueller matrices, Polarizer, Analyzer, Stokes vector.