Verdet constant determination of dielectric media using a new versatile, portable and low-cost magneto-optical rotator

The full details of a newly developed versatile, portable and low-cost magneto-optical device for the accurate determination of Verdet constant over the wavelength range of 400-480 nm in undergraduate physics and chemistry labs are presented. The elevated sensitivity of the device is achieved by using a semiconducting photodiode detector coupled with an electronic circuit board, which is configured to autonomously record the finest rotation angle in the polarization direction of the transmitted light relative to a reference polarizer. Two different mechanisms to generate a strong coaxial magnetic field of ∼1.34 T are presented, using either a ring neodymium permanent magnet or a solenoid fed by a lithium-ion battery cell. Due to its versatility, portability and low-cost, the presented device is expected to replace most currently existing bulky and expensive setups.