Open-path remote sensing for multi-species gas detection using a broadband optical parametric oscillator

Oguzhan Kara, Frazer Sweeney, Marius Rutkauskas, Carl Farrell, Christopher G. Leburn*, Derryck T. Reid

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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We demonstrate path-integrated simultaneous concentration measurements of water, methane and ethane, measuring spectra across the 3.1-3.5-μm range using 0.05 cm-1 resolution Fourier-transform spectroscopy in-line with an ultrafast optical parametric oscillator and a simple, non-compliant target. Illumination spectra were extracted from a fitting procedure which simultaneously minimized the rms error between the experimental spectrum and a synthetic spectrum calculated from the envelope and a fitted mixture of PNNL or HITRAN absorbance data for water, methane and ethane. Simultaneous methane, ethane and water measurement at 30-m range were initially performed. Indoor measurements launched light from the OPO through a 20-cm-long gas cell containing a 1.5±0.15% ethane-in-air mixture. Light was reflected from a rough Al-foil target. Best-fit concentrations were determined to be 1.15% (water), 1860 ppb (methane) and 1.37 % (ethane). The methane background value is consistent with reported ambient levels. Respective water and ethane values were consistent with the ambient relative humidity. The second experiment demonstrated real-time methane emission measurement at 70-m range. A 2% methane:air mix was released for 100 seconds at a rate of 103 μgs-1 at a distance of 65 m from the OPO. The signal was recorded from a simple target of rough aluminum foil situated 70 m from the OPO, with the beam passing near the emission point. This work demonstrates our ability to extract concentration data from a single spectrum with no need for averaging, which provides a real-time and quantitative monitoring capability.

Original languageEnglish
Title of host publicationReal-Time Measurements, Rogue Phenomena, and Single-Shot Applications V
EditorsDaniel R. Solli, Georg Herink, Serge Bielawski
ISBN (Electronic)9781510632943
ISBN (Print)9781510632936
Publication statusPublished - 2 Mar 2020
EventSPIE LASE 2020 - San Francisco, United States
Duration: 1 Feb 20206 Feb 2020

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceSPIE LASE 2020
Country/TerritoryUnited States
CitySan Francisco


  • Broadband
  • FTIR Spectroscopy
  • Multi-Species
  • Open Path Spectroscopy
  • Optical Parametric Oscillator
  • Remote Sensing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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