Jana Jágerská

Trace gases such as methane and carbon dioxide make up less than 1% of the Earth’s atmosphere, yet they play important roles in climate change, industrial processes and human health. Measuring these gases normally requires large and expensive instruments. The UiTrace project aimed to bring this technology onto a photonic chip, improving scalability and robustness while reducing instrument size, cost and the volume of gas required for analysis.

The principal invention behind the project was the development of novel microscopic suspended waveguides operating in the mid-infrared spectral range. These waveguides greatly increased the interaction between light and the surrounding gas and decreased noise, leading to increased sensitivity. When combined with dedicated mid-infrared lasers, they allowed to selectively identify gases through their unique  spectral absorption fingerprints, yielding a calibration-free and interference-robust method. Using these devices, the team detected carbon dioxide and methane at concentrations as low as 20 and 200 parts per billion (ppb), respectively, which is nearly 1,000 times improvement in sensitivity than in earlier on-chip approaches. UiTrace also produced the first on-chip sensors capable of distinguishing carbon dioxide isotopes at very low concentrations and measuring isotope ratios with high precision.