By Patricia Daukantas
I can’t say it any better than the press release did: “Finally, an optical frequency comb that visibly lives up to its name.”
Researchers in the United States and Germany have collaborated on a 10-GHz frequency comb with spectral coverage from about 470 to 1130 nm. Unlike other combs, a simple grating spectrometer can spatially separate this comb’s “teeth” so that they are visible with the human eye.
OSA Fellow Scott A. Diddams of the U.S. National Institute of Science and Technology (NIST), working with Albrecht Bartels of the University of Konstanz (Germany) and Dirk Heinecke of Konstanz and NIST, published their work in the October 30 issue of Science.
The authors say that the comb’s modes could serve as precise frequency markers for calibration of astronomical spectrographs and for many other spectroscopic uses. As has been noted in this blog in the past, frequency-comb spectroscopy is being explored as an important tool for detecting planets orbiting stars other than the Sun.
Incidentally, this Science article was published on the 68th birthday of OSA Honorary Member Theodor Hänsch, who shared part of the 2005 Nobel Prize in physics with OSA Honorary Member (and longtime NIST scientist) John L. “Jan” Hall for their pioneering work on – you guessed it – frequency combs.
Above: Photographs of four different regions of the new optical frequency comb. The light is filtered through a grating spectrometer and photographed with a digital camera through a microscope. Each visible line or "tooth" is an individual frequency in the comb, which spans the visible spectrum from red to blue. More than 1,500 such photos would need to be lined up to show the entire comb. (Photo credit: S. Diddams/NIST)