Detection of eddy currents with a new laser-supported eddy current sensor

Uwe Radtke; Horst-Artur Crostack; M. Maass

doi:10.1117/12.281180

17 September 1997 Detection of eddy currents with a new laser-supported eddy current sensor

Uwe Radtke, Horst-Artur Crostack, M. Maass

Proceedings Volume 3098, Optical Inspection and Micromeasurements II; (1997) https://doi.org/10.1117/12.281180
Event: Lasers and Optics in Manufacturing III, 1997, Munich, Germany

Abstract

An optical configuration for a new laser supported eddy current sensor was developed and tested. In the arrangement the induction of eddy currents is conventionally performed with an excitation coil above the object under test. For the detection of the magnetic field a suitable crystal, which is integrated in the excitation coil, in combination with a detection laser beam running parallel to the axis of the coil is used. In the presence of a magnetic field, the Faraday-effect in this crystal leads to a rotation of the polarization of the detection laser beam. With the help of a suitable optical arrangement this rotation of the laser polarization is transformed in a change of light intensity, which is analyzed by a photodiode. The special advantage of this arrangement is, that by a focusing of the detection laser beam a measurement of the magnetic field with a high spatial resolution can be achieved. In this paper the basic physics and the design of the sensor will be describe. First results of experimental investigations concerning the resolution power will be presented and compared with conventional eddy current sensors.

Citation Download Citation

Uwe Radtke, Horst-Artur Crostack, and M. Maass "Detection of eddy currents with a new laser-supported eddy current sensor", Proc. SPIE 3098, Optical Inspection and Micromeasurements II, (17 September 1997); https://doi.org/10.1117/12.281180

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