Measuring the Faraday effect: an instructive experiment

Abstract As discovered by Michael Faraday in 1845, the Faraday effect is a magneto-optical phenomenon in which the plane of polarization of a linearly polarized beam of light is rotated whenever the beam of light passes through a transparent material placed in a magnetic field. In this paper, we present a science project that uses a laser, solenoid, polarizing film, acrylic water cell, and photoresistor to measure the rotation angle of light in water under a magnetic field. Details of the optical layout, solenoid construction, calibration, and measurement procedure are given along with a comparison with published data. This project presents an accessible introduction to magneto-optics and the methods used in optical studies by demonstrating a feasible, low-cost, and instructive experiment for students, science hobbyists and educators interested in magneto-optics.