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17 September 1997 Detection of eddy currents with a new laser-supported eddy current sensor
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Proceedings Volume 3098, Optical Inspection and Micromeasurements II; (1997)
Event: Lasers and Optics in Manufacturing III, 1997, Munich, Germany
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.
© (1997) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
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);

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