Dual Comb Spectroscopy for Electronic Fingerprinting

Abstract:

Dual Comb Spectroscopy 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). Especially molecular gasses of astrophysical and environmental relevance have strong and congested absorption characteristics in this spectral region (few examples: NO2, CO, SO2, HCHO). I will present our latest efforts on expanding dual comb spectroscopy via nonlinear frequency up-conversion into the ultraviolet region. The challenges include UV frequency comb generation with a high photon flux, efficient UV interferometry and fast UV signal detection [4].

References

[1] B. 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 Photonics4, 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)