Long-Term Laser Frequency Stabilization Using a Molecular Beam.
Final rept. 1 Jan 76-31 Dec 77,
MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
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The aim of the research program was the long-term stabilization of the frequency of the 5145 A argon ion laser by using an I2 resonance, observed in a molecular beam, as a reference. The major accomplishments and the status of the program are outlined below. The 5145 A argon ion laser has been locked to a hyperfine transition in a molecular beam of I2. Two methods were used to measure the long-term frequency drift. The first method is the simpler one, and only requires one additional molecular beam apparatus. Here, the laser frequency drift is monitored by measuring the shift of the laser frequency with respect to the center of the same I2 transition observed in an independent molecular beam. In the second and more conventional method, two argon lasers are independently stabilized to adjacent I2 transitions in independent molecular beams. The two laser outputs are mixed on a fast photodiode, and the resulting beat frequency gives an accurate measure of frequency stability. Both methods yielded similar results i.e., better than one-part-in 10 to the 13th power in an integration time of about 100 seconds. This was the highest stability achieved in the visible region of the spectrum at the time the measurements were made. The shift in the stabilized laser frequency as a function of laser intensity was found to be less than two-parts-in 10 to the 14th power for a 1 change in laser intensity at I mW. This value is still an upper limit at present, pending a more detailed study.
- Lasers and Masers
- Atomic and Molecular Physics and Spectroscopy
- Nuclear Physics and Elementary Particle Physics