Optical frequency combs—which combine the metrological virtues of white light and single-wavelength lasers by generating hundreds or thousands of tight, sharp, evenly spaced frequency peaks covering a wide swath of the spectrum—are increasingly used to calibrate electromagnetic radiation, refine time measurements, identify spectroscopic signatures, find exoplanets, and even define mass in quantum-mechanical terms.
Conventional optical frequency comb devices are generally table-top size, driven by high-powered femtosecond lasers, and take hours or even weeks to build around optical cavities. What’s more, they must be fabricated in clean-room facilities using equipment that costs anywhere from US $1 million to $10 million.
In two recent papers, though, researchers at the National Institute of Standards and Technology in Boulder, Colo., report on the construction and performance of an optical frequency comb apparatus built around optical cavities machined from fused quartz using $10,000 worth of equipment, most of it for a carbon-dioxide laser. Making the cavity takes less than a minute. And in another minute, the researchers say, the cavity resonator can be teamed with a small, low-powered infrared laser to produce a usable optical frequency comb powered by a small, low-powered infrared laser.
A portable comb for more precise calibration and measurement is possible! Read the rest of the article here!