Fast magneto-optical spectrometry by spectrometer.

Time efficient measurement of the spectroscopic magneto-optical (MO) activity of materials has always been desirable. In conventional MO systems, the monochromator produces quasi-monochromatic light in a narrow wavelength window. Therefore, to measure the spectroscopic MO activity, a large number of measurements over the full spectra is required to obtain satisfactory wavelength resolution and thus is very time consuming. Here, we develop a novel system that is capable of fast measurement of the MO activity by only one white light source, two polarizers, one achromatic quarter-wave plate, and one spectrometer. This system is flexible from UV to IR region, only depending on the power spectra of light source and sensitivity of the detector at the corresponding wavelengths. As examples, we measured the intriguing optic and MO activity in glass, ferromagnetic thin film, and bulk GaAs in the visible to near infrared region. The results of glass demonstrated a minimum resolvable Faraday rotation angle of 0.004° by the currently equipped system.