Researchers have developed a new way of operating miniature quantum cascade lasers (QCLs) to rapidly measure the absorption spectra of different organic molecules in the air simultaneously. The technique offers a sensitive method for detecting low concentrations of volatile organic compounds (VOCs), improving the ability to track how these compounds affect human health, industrial processes and ambient air quality. The new system also could improve the reliability of breath alcohol tests by more selectively distinguishing between ethanol and the other gases people exhale.
QCLs are made from multiple layers of semiconductors arranged to boost photon emissions by exploiting quantum effects. The researchers designed a QCL based setup that measures compounds absorbing electromagnetic radiation across a wide spectrum with a single laser, a task that would have previously required multiple lasers working together.