ELFIS - Electronic Fingerprint Spectroscopy

Media Service Tracking the effects of sunlight TU Graz physicist and START prize winner Birgitta Schultze -Bernhardt is working on a new measurement technology that allows UV-light-induced chemical processes to be investigated with an unprecedented level of detail. Ultraviolet light is particularly high-energy light that triggers numerous chemical reactions: it can destroy organic bonds, but also contribute to their formation. The sun`s UV radiation, for example, is responsible for atmospheric trace gases combining to form ground-level ozone, the harmful summer smog. Little is known about the exact mechanisms of such UV-light-induced processes, since they cannot yet be investigated with the necessary level of detail using current laser measurement techniques. Why is this? There is no laser that emits directly in the UV range, i.e. light in the short-wave range of UV radiation the wavelength of UV light is between 100 and 400 nanometers and is therefore much smaller than visible light. Making UV light "visible" Birgitta Schultze-Bernhardt wants to solve this problem with a new measuring method. She is working on the development of electronic fingerprint spectroscopy (ELFIS), which should enable more precise investigations in the UV range. The concept involves converting the light of an infrared laser into high- energy ultraviolet light. Two such high-energy light beams are sent through a material sample and "swallowed" to different degrees inside the material. Using two different UV laser light beams finally allows the high optical frequencies to be measured with a conventional photodiode. The result is a kind of fingerprint that provides information about the chemical components of the sample and its optical properties. Gradual implementation The development of the procedure is done in stages. In a first phase, Schultze-Bernhardt and her teams at the Institute of Experimental Physics and the Institute of Materials Physics are working on a spectrometer that works in the visible (green) spectral range and can detect trace gases such as nitrogen dioxide. Finally, a spectrometer in the near UV spectral range could be realistic within a year. At the end of the phased plan, Schultze-Bernhardt hopes to have a spectrometer "with which we will be able to view light-induced processes in a broad spectral range, in real time with high spectral and temporal resolution at the same time." Short biography Birgitta Schultze-Bernhardt Birgitta Schultze-Bernhardt (born 1981 in Erlangen, Germany) is a researcher at the Institute of Experimental Physics and the Institute of Materials Physics at Graz University of Technology. Schultze- Bernhardt is intensively engaged in laser technologies for the measurement of light -induced processes and received her doctorate at the Faculty of Physics of the Ludwig-Maximilians-University in Munich and at the Max Planck Institute for Quantum Optics in Garching under Nobel Prize winner Theodor W. Hänsch. Contact: Birgitta SCHULTZE-BERNHARDT Dipl.-Phys. (Univ.) Dr.rer.nat. TU Graz | Institute of Experimental Physics and Institute of Materials Physics Phone: +43 316 873 8663 schultze-bernhardt@tugraz.at

Tracking the Effects of Sunlight: A Breakthrough in Measuring Chemical Reactions Birgitta Schultze-Bernhardt, a physicist at TU Graz and winner of the prestigious START prize, has developed an innovative measurement technology that allows scientists to study light-induced chemical processes with remarkable precision. Ultraviolet (UV) light, a form of high-energy radiation, plays a crucial role in triggering various chemical reactions. It can break down organic compounds or even help create them. For instance, the sun's UV rays contribute to the formation of ground-level ozone, a key component of harmful summer smog. However, the intricate details of these UV-induced processes have remained largely unexplored due to limitations in current laser measurement technologies. The challenge lies in the fact that there is no laser capable of emitting light in the UV range, which spans wavelengths from 100 to 400 nanometers-far shorter than that of visible light. To address this limitation, Schultze-Bernhardt has pioneered a method called electronic fingerprint spectroscopy (ELFIS), which aims to enhance the investigation of both visible (VIS) and UV light after its interaction with different gaseous samples. This technique involves converting the light from an infrared laser into higher-energy light that falls within the VIS/UV spectrum. By directing two high-energy light beams through a material sample, researchers can measure how these beams are absorbed to varying degrees. This process yields a unique "fingerprint" that reveals information about the sample's chemical makeup and optical characteristics. The development of this technology has been gradual. Initially, Schultze-Bernhardt and her team created a spectrometer capable of detecting trace gases like nitrogen dioxide in the visible spectrum. This device was successfully deployed in field campaigns to monitor nitrogen dioxide levels in the city of Graz. Building on this success, they later developed a spectrometer that operates in the near UV spectrum, achieving high-resolution spectroscopy of formaldehyde-another environmentally significant trace gas. This new spectrometer is notable for covering an unprecedented ultra-broadband spectral range in the UV. With these advancements, Schultze-Bernhardt's work is set to greatly enhance our understanding of the complex chemical interactions driven by sunlight, with potential implications for environmental monitoring and public health.