Monday, 02 June, 2025
at Helmut Rauch Lecture Hall, Atominstitut, TU Wien
Stadionallee 2, 1020 Wien

Electronic Fingerprint Spectroscopy with Frequency Combs

Dual Comb Spectroscopy (DCS) combines high spectral resolution with broad spectral coverage and short measurement times. In the recent years, this spectroscopic method has proven its capabilities in molecular spectroscopy in different spectral regions ranging from the visible across the infrared spectral region into the THz domain [1-3]. The UV has so far been neglected for fingerprinting although electron transitions are as element specific as rovibrational transitions and the corresponding absorption cross sections can be huge (> 100 Mb). Additionally, DCS combined with pump probe sample interaction provides a unique combination of ultra-high spectral (GHz) and high temporal (fs) resolution. This can explore photo-induced dynamics in atoms and molecules involving transient effects such as level splittings, shifts and quantum beatings at a new level of detail.

I will present our first efforts and latest results on expanding dual comb spectroscopy via nonlinear frequency up-conversion into the ultraviolet region [4-6]. Further application possibilities aim at environmental sensing in the field [7] and in real time [8].

[1] Bernhardt, A. Ozawa, P. Jacquet, M. Jacquey, Y. Kobayashi, T. Udem, R. Holzwarth, G. Guelachvili, T. W. Hänsch, and N. Picqué, „Cavity-enhanced dual-comb spectroscopy,“ Nature Photonics 4, 55–57 (2009).

[2] T. Ideguchi, S. Holzner, B. Bernhardt, G. Guelachvili, N. Picqué, and T. W. Hänsch, „Coherent Raman spectro-imaging with laser frequency combs.,“ Nature 502, 355–8 (2013).

[3] G. Hu, T. Mizuguchi, R. Oe, K. Nitta,X. Zhao, T. Minamikawa, T. Li, Z. Zheng and T. Yasui, “Dual terahertz comb spectroscopy with a single free-running fibre laser”, Scientific Reports 8, 11155 (2018)

[4] V. Schuster, C. Liu, R. Klas, P. Dominguez, J. Rothhardt, J. Limpert, and B. Bernhardt, “Ultraviolet dual comb spectroscopy: a roadmap”, Optics Express 29, Issue 14, 21859-21875 (2021)

[5] Fürst, L., Kirchner, A., Eber, A., Siegrist, F., Di Vora, R., and Bernhardt, B., Broadband near-ultraviolet dual comb spectroscopy, (2024), Optica, Vol. 11, Issue 4, 471, (2024)

[6] L. Fürst, A. Eber, M. Pal, E. Hruska, C. Hofmann, I. Gordon, M. Schultze, R. Breinbauer, B. Bernhardt, Ultra-resolution photochemical sensing, arXiv:2501.07350 (2025)

[7] A. Eber, L. Fürst, F. Siegrist, A. Kirchner, B. Tschofenig, B., R. Di Vora, A. Speletz and  B. Bernhardt Coherent field sensing of nitrogen dioxide, Optics Express, Vol. 32, Issue 4, pp. 6575-6586 (2024)

[8] A. Eber, Ch. Gruber, M. Schultze, B. Bernhardt and M. Ossiander, Streaming Self-Corrected Dual-Comb Spectrometer, https://doi.org/10.48550/arXiv.2503.07005 (2025)

Host: Thorsten Schumm

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Program

17:00 Get Together with Snacks

17:30 VCQ Student Talk

17:45 VCQ Colloquium Talk