Applied Physics B

, Volume 107, Issue 2, pp 275–283

Ultra-sensitive carbon monoxide detection by using EC-QCL based quartz-enhanced photoacoustic spectroscopy

  • L. Dong
  • R. Lewicki
  • K. Liu
  • P. R. Buerki
  • M. J. Weida
  • F. K. Tittel
Article

DOI: 10.1007/s00340-012-4949-1

Cite this article as:
Dong, L., Lewicki, R., Liu, K. et al. Appl. Phys. B (2012) 107: 275. doi:10.1007/s00340-012-4949-1

Abstract

A quartz-enhanced photoacoustic spectroscopy (QEPAS) based sensor for carbon monoxide detection at ppbv levels was developed with a 4.65 μm external-cavity quantum cascade laser operating both in continuous wave (cw) and pulsed modes. A 23-fold enhancement of the measured CO signal amplitude was obtained when water vapor, acting as a catalyst for vibrational energy transfer, was added to the targeted analyte mixture. In the cw mode, a noise-equivalent sensitivity (NES, 1σ) of 2 ppbv was achieved at a gas pressure of 100 Torr, for 1-s lock-in amplifier (LIA) time constant (TC), which corresponds to a normalized noise equivalent absorption coefficient (NNEA) of \(1.48\times 10^{-8}~\mathrm{cm}^{-1}\,\mathrm{W}/\sqrt{\mathrm{Hz}}\). In the pulsed mode, the determined NES and NNEA were 46 ppbv and \(1.07\times 10^{-8}~\mathrm{cm}^{-1}\,\mathrm{W}/\sqrt{\mathrm{Hz}}\), respectively, for a 3-ms LIA TC at atmospheric pressure with a laser scan rate of 18 cm-1/s and a 50 % duty cycle. An intercomparison between cw and pulsed QEPAS-based CO detection is also reported.

Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • L. Dong
    • 1
  • R. Lewicki
    • 1
  • K. Liu
    • 1
  • P. R. Buerki
    • 2
  • M. J. Weida
    • 2
  • F. K. Tittel
    • 1
  1. 1.Department of Electrical and Computer EngineeringRice UniversityHoustonUSA
  2. 2.Daylight Solutions, Inc.San DiegoUSA

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