Magneto-optical method for measuring mechanical quantities

The progress of many optical methods for measuring geometrical quantities is restricted because of a lack of appropriate light detection techniques. Existing photodetectors-charge-coupled devices and position sensitive detectors-do not comply with the demand of high spatial accuracy combined with high sampling rates. In this paper a magneto-optical method for measuring the positions of light beams is described. It is based on spatial light modulation produced by domain wall motion in an orthoferrite crystal. The presented method provides a measurement accuracy of 0.8 μm and a sampling time of about 1 μs.