Accurate optical sensing

Hydrogen sensors have been the focus of research for many years. Scientists working for the University of Georgia and South Carolina’s Savannah River National Laboratory have now found a way to make it extremely easy to detect even minute traces of the gas. A research article about their new optical method for hydrogen sensing was published in the Nature Communications journal in April. “Our spark-free, optical-based hydrogen sensors detect the presence of hydrogen without electronics, making the process much safer,” said Tho Nguyen, an associate professor in the university’s Franklin College of Arts and Sciences and, together with the laboratory’s George Larsen, the co-principal investigator on the project.
The sensors take advantage of the propensity of thin metal films to absorb hydrogen, leading to changes in light transmission. These subtle changes are large enough to be picked up by a detector in the blink of an eye, producing a signal. The units’ response time and sensitivity can be adjusted to fit the material used (e.g., palladium or cobalt) and the size of the metal film.
“With our intensity-based optical nano sensors,” said Nguyen, “we [can detect hydrogen] at 2 parts-per-million,” adding that the response time of the new units is 0.8 seconds. That makes them 50 times more sensitive than other optical hydrogen sensors and 20 percent faster than the best available optical device reported in the literature.

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