Smart New Laser Technology Can Monitor Greenhouse Gases Faster

New laser technology, known as free-form dual-comb spectroscopy, quickly measures gases of interest by homing in on the most information-rich parts of a sample

Scientists at the National Institute of Standards and Technology (NIST) have developed a new laser-based technique that could dramatically improve our ability to analyze a variety of materials and gases, including greenhouse gases. This new method, called “free-form dual-comb spectroscopy,” offers a faster, more flexible and more sensitive way to analyze substances in the air and other materials.

In this specific study, published in Nature Photonics, researchers demonstrated that their laboratory-based system could detect a single gas, in this case the potent greenhouse gas methane, with 22 times higher sensitivity than a traditional dual-comb system. This increased sensitivity could one day help identify small leaks or emissions that might otherwise go unnoticed, potentially aiding in efforts to combat climate change.

“The flexibility of our system means it could be adapted for a wide range of applications,” said NIST researcher Esther Baumann. “In the future, we might see more versatile and efficient sensors based on this technology in everything from air quality monitors to food safety detectors to studying how materials burn or assessing muscle health noninvasively.”

Free-form dual-comb spectroscopy may be a mouthful to pronounce, but understanding how this technology works can be more easily digested by breaking it down into several parts that work seamlessly together.

The heart of this method lies in the Nobel Prize-winning optical frequency comb, a laser tool that produces light at a series of equally spaced, precise frequencies that resemble the teeth of a comb. These frequency combs are used for a variety of purposes, from precision timekeeping to medical diagnostics and even the search for elusive dark matter.

The “dual-comb” aspect of this technology refers to the use of two optical frequency combs working together. This approach enables rapid, precise measurements of substances by analyzing how they interact with the light from both combs. This technique is much faster than a single comb and can provide more detailed information than many traditional spectroscopy methods.

“Free-form” refers to the flexibility in highly precise frequency comb control that has recently become possible. The frequency combs emit light pulses that are just 100 femtoseconds in duration. Inside each of these brief light bursts, there’s an electric field that vibrates extremely rapidly, millions of millions of times per second. The ability to quickly and accurately control this fast light allows researchers to improve and adjust how they take measurements.

Find more information here