Faraday current sensor using space-variant analyzers

A Faraday current sensor using spatially inhomogeneous analyzers is presented. In the proposed optical architecture, the light waves coming from the sensor head travel in free space reaching a space-variant analyzer, and then they are acquired by a (one - or two-dimensional) photodetector array. This allows a full determination of the Faraday rotation induced by the electrical current, even in the case of a nonideal optical system (e.g., analyzer with poor polarization ratio). The proposed method resembles well-known techniques of phase-shifting interferometry. Validation experiments using linearly variant and azimuthal (radial) analyzers are presented and different detection schemes are compared.