EGU2020-4213
https://doi.org/10.5194/egusphere-egu2020-4213
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Prism-based Broadband Optical Cavity (400 – 1600 nm) for High-Sensitivity Trace Gas Sensing by Cavity Enhanced Absorption Spectroscopy

Weidong Chen1, Gaoxuan Wang1, Lingshuo Meng1, Qian Gou2, Azer Yalin3, Tong Nguyen Ba1, Cécile Coeur1, and Alexandre Tomas4
Weidong Chen et al.
  • 1Université du Littoral Côte d'Opale, France (chen@univ-littoral.fr)
  • 2School of Chemistry and Chemical Engineering, Chongqing University, China
  • 3Department of Mechanical Engineering, Colorado State University, USA
  • 4IMT Lille Douai, Département Sciences de l’Atmosphère et Génie de l’Environnement, France

The use of high reflectivity dielectric mirrors to form a high finesse optical cavity allows one to achieve long optical path lengths of up to several kilometres for high-sensitivity spectroscopy applications [1]. However, the high reflectivity of a dielectric mirror is achieved via constructive interference of the Fresnel reflection at the interfaces produced by multilayer coatings of alternate high and low refractive index materials. This wavelength-dependent coating limits the bandwidth of the mirror's high reflectivity to only a few percent of the designed central wavelength [2].

In this paper, we report on the development of a novel optical cavity based on prism used as cavity reflector through total internal reflection combined with Brewster angle incidence [3], which offers a high-finesse optical cavity operating in a broadband wavelength region from 400 to longer than 1600 nm. Cavity Enhanced Absorption Spectroscopy (CEAS) of NO2, NO3, and H2O vapor was applied to determine the achieved prism reflectivity over a broad spectral range from 400 nm to 1600 nm.

Experimental details and preliminary results will be presented. The developed prism-based cavity is specifically adapted for the needs of broadband measurement of multi-molecular absorber or/and wavelength-dependent extinction coefficient of aerosols over a broad spectral region.

Acknowledgments. This work is supported by the French national research agency (ANR) under the CaPPA (ANR-10-LABX-005), the MABCaM (ANR-16-CE04-0009) and the MULTIPAS (ANR-16-CE04-0012) contracts. The authors thank the financial support from the CPER CLIMIBIO program.

REFERENCES

[1] S. S. Brown, "Absorption spectroscopy in high-finesse cavities for atmospheric studies", Chem. Rev. 103 (2003) 5219-5238.

[2] G.R. Fowles, Introduction to Modern Optics, 2nd ed. (Rinehart and Winston, 1975), p. 328.

[3] B. Lee, K. Lehmann, J. Taylor and A. Yalin, "A high-finesse broadband optical cavity using calcium fluoride prism retroreflectors", Opt. Express 22 (2014) 11583-11591.

How to cite: Chen, W., Wang, G., Meng, L., Gou, Q., Yalin, A., Nguyen Ba, T., Coeur, C., and Tomas, A.: Prism-based Broadband Optical Cavity (400 – 1600 nm) for High-Sensitivity Trace Gas Sensing by Cavity Enhanced Absorption Spectroscopy, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4213, https://doi.org/10.5194/egusphere-egu2020-4213, 2020

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