Method and apparatus for Doppler frequency modulation of radiation
Abstract
A method and apparatus are described for frequency modulating radiation, such as from a laser, for optoacoustic detectors, interferometers, heterodyne spectrometers, and similar devices. Two oppositely reciprocating cats-eye retroreflectors are used to Doppler modulate the radiation. By reciprocally moving both retroreflectors, the center of mass is maintained constant to permit smooth operation at many Hertz. By slightly offsetting the axis of one retroreflector relative to the other, multiple passes of a light beam may be achieved for greater Doppler shifts with the same reciprocating motion of the retroreflectors.
- Publication:
-
National Aeronautics and Space Administration Report
- Pub Date:
- May 1980
- Bibcode:
- 1980nasa.reptS....M
- Keywords:
-
- Beams (Radiation);
- Doppler Effect;
- Frequency Modulation;
- Laser Outputs;
- Light Modulation;
- Retroreflection;
- Amplitude Modulation;
- Patents;
- Remote Sensors;
- Wind Measurement;
- Communications and Radar