EGU22-10136
https://doi.org/10.5194/egusphere-egu22-10136
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Ammonia Sensing with a Gain Switched Frequency Comb of 100 MHz Free Spectral Range using Off-Axis Cavity-Enhanced Absorption Spectroscopy

Albert A. Ruth1, Satheesh Chandran*1, Eamonn P. Martin2, Alejandro Rosado3, Erik P. Soderholm2, Justin K. Alexander4, Frank H. Peters4, and Prince M. Anandarajah2
Albert A. Ruth et al.
  • 1University College Cork, Environmental Research Institute & Physics Department, Cork, Ireland (*corresponding author: pmsc85@gmail.com)
  • 2Photonics Systems and Sensing Laboratory, School of Electronic Engineering, Dublin City University, Glasnevin, Dublin 9, Ireland
  • 3CEMDATIC - E.T.S.I Telecomunicación, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
  • 4University College Cork, Tyndall National Institute & Physics Department, Cork, Ireland

The usefulness of the equally spaced, phase-coherent, narrow-band spectral lines of a frequency combs (FC) for spectroscopy has long been recognized for applications in gas-phase sensing. Among the different type of frequency combs the gain switching of commercially available semiconductor lasers in the near IR has recently gained interest due to the simplicity and flexibility of this approach [1, 2]. In this study we present a custom-designed gain-switched frequency comb (GSFC) with a small free spectral range of merely 100 MHz [3]. This GSFC was passively coupled to a medium finesse (F = 520) cavity in off-axis configuration for the detection of ammonia (14NH3) in static dry air [4]. The absorption of ammonia was measured between 6604.5 and 6606.0 cm-1 using a Fourier transform spectrometer. More than 60 lines of the GSFC overlapped with the strongest ro-vibrational ammonia absorption features in that spectral region. With the cavity in off-axis configuration, an NH3 detection limit of ~5 ppmv in 20 s was accomplished in a static laboratory environment. The characterization and experimental performance of the GSFC and prototype spectrometer are presented in this contribution together with a discussion of the corresponding technical advantages and drawbacks, as well as the potential for alternative future applications.

Acknowledgement

This publication has emanated from research supported in part by Grants from Science Foundation Ireland with the numbers 21/FFP-A/8973, 15/CDA/3640, and 14/TIDA/2415. Financial support by Enterprise Ireland’s Commercialization Fund (CF 2017 0683) is also gratefully acknowledged.

References

[1] P.M. Anandarajah, R. Maher, Y. Xu, S. Latkowski, J. O’Carroll, S.G. Murdoch, R. Phelan, J. O’Gorman, L.P. Barry, IEEE Photonics J. 3 (2011) 112. Doi: 10.1109/jphot.2011.2105861

[2] M.D. Guitérrez-Pascual,V. Vujicic, J. Braddell, F. Smyth, P.M. Anandarajah, L.P. Barry, Opt. Lett. 42 (2017) 555. Doi: 10.1364/OL.42.000555

[3] A. Rosado, E. P. Martin, A. Pérez-Serrano, J. M. G. Tijero, I. Esquivias, P. M. Anandarajah, Opt. Laser Technol. 131 (2020) 106392. Doi: 10.1016/j.optlastec.2020.106392

[4] S. Chandran, A.A. Ruth, E.P. Martin, J.K. Alexander, F.H. Peters, P.M. Anandarajah, Sensors 19 (2019) 5217. Doi: 10.3390/s19235217

How to cite: Ruth, A. A., Chandran*, S., Martin, E. P., Rosado, A., Soderholm, E. P., Alexander, J. K., Peters, F. H., and Anandarajah, P. M.: Ammonia Sensing with a Gain Switched Frequency Comb of 100 MHz Free Spectral Range using Off-Axis Cavity-Enhanced Absorption Spectroscopy, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10136, https://doi.org/10.5194/egusphere-egu22-10136, 2022.