Abnormal chopping effects on the signal of the metal-insulator metal diode (laser frequency measurement)

The authors report the experimental results concerning abnormally enhanced effects on the signal detection of point-contact MIM (metal-insulator-metal) diodes when an incident CO/sub 2/ laser beam is chopped at the resonant chopping frequencies with a mechanical chopper. The signal intensity with the chopping effect is about seven times as large as that without the chopping effect. The MIM diode is shown to have a very large S/N (signal/noise ratio) value at the resonant chopping frequencies for the low laser power in the IR regions.<>