Instrument for Measuring the Depolarization of Backscattered Light.
DEPARTMENT OF THE NAVY WASHINGTON D C
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The patent describes an instrument capable of obtainint information on the polarization properties of ocean waters. Operation of the instrument is as follows Light from a He-Ne laser passes through a rotating beam chopper, a rotating linear polarizer, and a light guide and an aperture to block spurious reflections into the scattering medium, generally seawater. A portion of the backscattered light is intercepted by an analyzer-detector module, and after amplification the detector output is displayed on an oscilloscope. The beam is chopped at 20 times the rotational frequency of the polarizer. This provides an a-c backscatter signal which is independent of detector drift and changes in background illumination, if detector ssaturation is avoided.
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