Polarization Rotation for Light Propagating Obliquely to the Direction of Magnetization: Theoretical Expression and Experimental Study in Magnetic Colloid with Large Linear Birefringence

Abstract

Magneto-optical polarization rotation was studied in materials magnetized in an arbitrary orientation with respect to the light beam propagation direction. The Jones matrix of these media was derived, as was a theoretical expression representing the polarization rotation for the linear polarization incident with an arbitrary azimuth. This theoretical expression was confirmed through an experimental study by using a magnetic colloid which shows a large linear birefringence along with a magnetic circular birefringence. The expression shows that, when the linear birefringence and dichroism are not small enough in relation to the circular birefringence, the polarization rotation is obviously not proportional to the magnetization component parallel to the light beam. Even when the linear birefringence and dichroism are small, the proportionality decreases as the light beam path becomes longer. For the incident linear polarization of the axis parallel or perpendicular to the plane defined by the magnetization and the light beam, this problem is less remarkable.