The Resonant Faraday Effect

The resonant Faraday effect occurs for radiation at frequencies close to the absorption lines of a magneto-active material. In the paper we present a theory for isolated absorption lines with Voigt profiles. The background source is also assumed to have a Voigt profile. The theory shows how the resonant Faraday effect can be used to determine relative transition probabilities, as well as the magnitude of the Lorentzian component of the line profiles.Experimental results for an argon plasma are presented and show that the relative transition probabilities of atomic transitions with a common lower level can be measured to an accuracy of ± 1%. For strong absorption lines, the Voigt "a" parameter can also be determined to an accuracy of 10%, even when the Doppler width is 14 times larger than the Lorentzian width.