The measurement of Faraday rotation angle by the frequency spectrum analysis

A novel method for measuring Faraday rotation angle by the frequency spectrum analysis is presented in this paper. The theoretical analysis and the experimental results demonstrate that Faraday rotation angle can be determined by the amplitude ratio of the signal's fundamental frequency to double frequency. A solenoid working on different voltages is used to produce different magnetic fields. The Faraday rotation angles in these magnetic fields have been measured. The linear fitting degree of the voltage and Faraday rotation angle is better than 99%.