Description

NB-Photonics seminar by prof. Jana Jágerská on Sensitive trace gas detection with photonic integrated circuits

Abstract: Mid-IR laser spectroscopy is a powerful technique for the detection of trace gases. It relies on unique absorption fingerprints of gas molecules in the IR, which give excellent detection specificity, and long interaction pathlengths between light and gas in multipass cells or cavities, which provide unprecedented sensitivity with detection limits beyond part-per-trillion (ppt). Yet, when it comes to on-chip systems, detection sensitivity decreases dramatically, by 5-6 orders of magnitude compared to high-end instruments realized with bulk optics. In my presentation, I will discuss the main challenges that still hinder realization of sensitive on-chip laser spectrometers: high losses of optical integrated waveguides, low confinement factors of light in the analyte, and fringes from reflections at defects and interfaces. I will show how these challenges can be addressed with appropriate waveguide designs, such as our thin-film free-standing waveguides that push the detection limits of on-chip devices from current 100 ppm to  10 ppb levels. I will also touch the topic of on-chip pre-concentration combined with spectroscopic trace gas detection.

Bio-Sketch

Originally from Slovakia, Jana Jágerská studied applied physics and electronics at the Czech Technical University in Prague, and continued her scientific career towards a doctorate in photonics at EPFL, Switzerland. During her postdoctoral fellowship at Empa/ETH in Zürich, she familiarised with spectroscopic methods for detection of greenhouse gases and air pollutants, and as a postdoc at UiT, she extended her expertise in optochemical on-chip detection. In 2017, she obtained an ERC Starting Grant simultaneously with two other larger Norwegian grants, which allowed her to start her research group at the Department of Physics and Technology at UiT. She has been employed as Associate Professor at UiT in Tromsø since 2018 and from 2020 as adjunct associate professor at NTNU in Trondheim. In her research, she combines the methods of nanophotonics and laser spectroscopy to develop miniature but highly performant sensors for sensitive and specific detection of methane and isotopes of carbon dioxide. Her sensors can be, for example, deployed in drone-conducted emission measurements in the Arctic, but also in industrial process control and medical diagnostics.