Faraday Rotation measurement of the Verdet Constant of SF-57 glass at 650 nm

Abstract

Light emitted from a laser was directed into a solenoid, with a glass rod inside, and then into a polarizer to measure the angle of rotation. As we changed the polarizer angle, the intensity of the light followed a cosine squared function. A Verdet constant is specific to each medium which describes the wavelength dependent optical strength. Three different methods were used to determine the Verdet constant of the glass rod (SF-57): 1) directly measuring the shift angle with and without an applied magnetic field, 2) measuring the voltage proportional to light intensity at a particular angle while changing the field, 3) using an alternating current to generate an alternating field to measure the corresponding alternating voltage. We measured a Verdet constant of 0.0189 \(\pm\) 0.00172 \(\frac{radians}{mT\cdot m}\), 0.01856 \(\pm\) 0.000156 \(\frac{radians}{mT\cdot m}\), and 0.017665 \(\pm\) 0.000609 \(\frac{radians}{mT\cdot m}\) for methods one, two and three respectively. These values of Verdet constants agree with the literature.

Aims

The Faraday Rotation of Polarized light is the rotation of the plane of polarization of light propagating through a medium due to the presence of a magnetic field. In this experiment, we aim to measure the Verdet constant of a glass rod (SF-57) through the Faraday Effect.