Optical Frequency Measurement: 40 Years of Technology Revolutions
J L. Hall
The past forty years have witnessed spectacular progress in precision measurements, beginning with the first coherent optical source, the HeNeCW laser, demonstrated in late 1960 by A. Javan. B. Bennett, and D. Herriott, at Bell Laboratories. Almost immediately, these pioneers of the stable laser epoch introduced optical heterodyne techniques to explore the stability of the laser's optical frequency, expecting the few milliHertz linewidth predicted by the Schawlow-Townes formula for phase diffusion, and instead finding myriad physical processes that broaden and jiggle optical frequencies far beyond that narrow range. After a huge time and learning effort, most of these technical limitations can now be overcome. considering that the central frequency is some 5 x 1014 Hz, comparison with a potential resolution of these few millihertz reveals a potential dynamic range of 1017 and generates an excitement which is palpable, perhaps increasingly so even today, almost forty years later. In plain language, this untapped dynamic range of resolution offers one of our best tools for discovering new physics, in just the next decimal.
IEEE Journal of Selected Topics in Quantum Electronics
optical frequency measurement, precision measurement, ultrafast lasers, untrastable lasers
Optical Frequency Measurement: 40 Years of Technology Revolutions, IEEE Journal of Selected Topics in Quantum Electronics
(Accessed June 10, 2023)