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Y. Didosyan, H. Hauser, J. Nicolics:
"Magneto-optical Measurements of Geometrical Quantities";
Poster: XVI IMEKO World Congress 2000, Wien; 09-25-2000 - 09-28-2000; in: "IMEKO 2000 Abstracts", (2000), 246.

Many optical methods of geometrical quantities' measurements need continuous, precise, and high speed determination of positions of light beams interacting with the measured surface. Existing photodetectors, namely charge-coupled devices (CCDs) and position sensitive detectors (PSDs) in many cases do not comply with these demands. We are developing a new device with superior characteristics. It is based on the domain wall motion in a transparent ferromagnet, a so-called orthoferrite. The velocity limit of the domain wall motion in orthoferrite crystals is extremely high: 20 km/s. The device consists of an orthoferrite plate, an analyzer and a single point photodetector. It can measure positions of the light spots continuously with submicrometric accuracy. The sampling rate of the measurements can reach1 MHz. The application of the device to the angular measurements is briefly described.