Modulated High Sensitivity Infrared Polarimeter.
Patent Application, Filed 24 Feb 92,
DEPARTMENT OF THE ARMY WASHINGTON DC
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A modulated Faraday rotation signal is produced by passing a linearly polarized laser beam through a semiconductor wafer sample in a modulated magnetic field that is induced in a electromagnet by a sine wave generator and driver coupled thereto. The rotation signal is normalized by dividing by a transmission signal produced by modulating the beam with a chopper that operates at a different frequency from the frequency of the driver. The result is a Faraday rotation measurement with high signal-to-noise ratio and compensation for laser drift in intensity and beam direction. Author
- Infrared Detection and Detectors