The wavelength dependence of the Faraday effect may be measured either sequentially at particular wavelengths using narrow band sources, or simultaneously at many wavelengths using a white-light or broadband source. We apply both methods to measure the wavelength dependence of the Verdet constant of a terbium gallium garnet crystal. We show that although the white-light measurement offers the advantage of requiring only one source, it is more prone to systematic errors than using multiple laser sources.
Maxwell, J. L., Hughes, I. G., & Adams, C. S. (2022). White-light versus discrete wavelength measurements of Faraday dispersion and the Verdet constant. European Journal of Physics, 43(1), Article 015302. https://doi.org/10.1088/1361-6404/ac31d3