A team led by Jun Ye, a physicist at JILA - a joint institute of the National Institute of Standards and Technology and the University of Colorado at Boulder - demonstrated an optical technique for simultaneously identifying tiny amounts of a broad range of molecules in the breath, potentially enabling a fast, low-cost screening tool for disease.

The researchers analyzed human breath with frequency combs, which are generated by a laser specially designed to produce a series of very short, equally spaced pulses of light. The laser generates light as a series of very narrow frequency peaks equally spaced - like the teeth of a comb - across a broad spectrum. By detecting which colors of light were absorbed and in what amounts, the researchers could detect specific molecules and their concentrations.

The optical comb approach allows the researchers to simultaneously analyze a very broad spectrum, covering many possible molecular compounds with high precision, frequency resolution, and sensitivity. The technique could lead to one of the first widespread applications of frequency combs.

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