An ultrasonic shutter for noise reduction in real-time optical correlators.
A coherent optical correlator can operate as a generator of complex waveforms when it is driven by a short-duration carrier pulse. However, the poor signal-to-noise ratio which results usually precludes operation in this mode. The ultrasonic shutter described herein can improve the signal-to-noise ratio by a factor approaching the time-bandwidth product of the system. No moving mechanical parts are involved.
Maloney
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