Dual-Comb Spectroscopy Instrument for Remote Sensing

• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: Funded in 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 531846023

Modern quantum technologies in atomic and molecular physics as well as quantum optics enable measurements in the environment at a new level of sensitivity and resolution, thus creating a knowledge base for sustainable resource use and effective and verifiable climate protection. Different methods have already found their way from being used in the context of investigating fundamental science questions to application in environmental physics. In Heidelberg we have already undertaken the step from single particle detection in quantum gas experiments to trace analysis at single atom level for dating of water and ice relevant in environmental science. With this proposal, we would like to undertake another step of transferring knowhow in the quantum optics community which is not yet at the stage of being directly commercially available for remote sensing i.e. dual comb spectroscopy. In recent years it has been demonstrated that dual comb spectroscopy (DCS) is applicable to remote sensing and we would like to apply and benchmark this method with state-of-the-art Fourier-transform spectroscopy available in Heidelberg. Here, we apply for a spectroscopy setup which allows for the first steps of entering in this technology and with that setting the stage for a new research direction in Heidelberg. This project will be pushed forward by a team of experts in the field of quantum optics (Prof. Oberthaler) and environmental physics and remote sensing (Prof. Butz). The instrument will consist of two ultra-stable frequency comb setups which are highly controlled and shall be locked to an absolute frequency standard to ensure mutual coherence. This is the prerequisite for transferring the spectral properties from the optical domain to the radio frequency domain directly detected with a single, fast and sensitive photon detector. The performance of the setup will be constantly monitored with a reference gas sample in the lab, which will also be used to explore new detection schemes to optimize signal to noise for certain molecular species. For remote sensing, the light output will be transferred to a long open-path setup over the city of Heidelberg, where special care and adaptions have to be installed to ensure the optimal performance of the dual comb spectroscopy. With the additional level of spectral control, the highest sensitivity for specific molecules will be implemented and will act as a test case for future specifically designed laser systems finding application in different monitoring and detecting campaigns in environmental physics. The dual-comb setup will act as the basis for further developments which ultimately will lead to a new level of quality of remote sensing building on quantum optical techniques.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Dual-Comb-Spektrometer für Fernerkundung
• Instrumentation Group: 5700 Festkörper-Laser
• Applicant Institution: Ruprecht-Karls-Universität Heidelberg
• Leader: Professor Dr. Markus Kurt Oberthaler