Spectrophone stabilized laser with line center offset frequency control
Continuous offset tuning of a frequency stabilized cw gas laser is achieved by using a spectrophone filled with the same gas as the laser for sensing a dither modulation, detecting a first or second derivative of the spectrophone output with a lock-in amplifier, the detected output of which is integrated, and applying the integrator output as a correction signal through a circuit which adds to the dither signal from an oscillator a dc offset that is adjusted with a potentiometer to a frequency offset from the absorption line center of the gas, but within the spectral linewidth of the gas. Tuning about that offset frequency is achieved by adding a dc value to the detected output of the dither modulation before integration using a potentiometer. Tuning may also be achieved by changing the amplitude of dither modulation, or changing the pressure of the spectrophone gas, or any combination of these three tuning parameters which affect the amount of offset of the stabilized frequency from line center.
- Assignee:
- Natl. Aeronautics and Space Administration
- Patent Number(s):
- US 4434490
- OSTI ID:
- 6893871
- Country of Publication:
- United States
- Language:
- English
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