Magnetooptic Sensor Based on Electrogyration Compensation for Faraday Effect in Lead Molybdate Crystal

A novel magnetooptic sensor is proposed which is based on electrogyration compensation for the Faraday rotation angle in single lead molybdate (PbMoO4, PMO) crystal. The optical sensing unit is only composed of two polarizers and one single PMO crystal exhibiting both the Faraday and electrogyration effects. AC 50-Hz magnetic field in the range of 167 Gs has been measured by the method of electrogyration compensation, and the nonlinear error is <1.2%. The compensating voltage is similar to 16 V/Gs for a block of PMO crystal with 5 mm in length. Verdet constant of the PMO crystal sample has also been measured for light wavelength of 635 nm, and it is similar to 51.6 +/- 1.1 rad. T-1.m(-1). The proposed magnetooptic sensor provides a promising closed-loop measurement method of current, magnetic field, and Verdet constant.