Diode laser detection of greenhouse gases in the near-infrared region by wavelength modulation spectroscopy: pressure dependence of the detection sensitivity

Takashi Asakawa; Nozomu Kanno; Kenichi Tonokura

doi:10.3390/s100504686

Diode laser detection of greenhouse gases in the near-infrared region by wavelength modulation spectroscopy: pressure dependence of the detection sensitivity

Sensors (Basel). 2010;10(5):4686-99. doi: 10.3390/s100504686. Epub 2010 May 6.

Authors

Takashi Asakawa¹, Nozomu Kanno, Kenichi Tonokura

Affiliation

¹ Department of Chemical System Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan. asakawa@esc.u-tokyo.ac.jp

Abstract

We have investigated the pressure dependence of the detection sensitivity of CO(2), N(2)O and CH(4) using wavelength modulation spectroscopy (WMS) with distributed feed-back diode lasers in the near infrared region. The spectral line shapes and the background noise of the second harmonics (2f) detection of the WMS were analyzed theoretically. We determined the optimum pressure conditions in the detection of CO(2), N(2)O and CH(4), by taking into consideration the background noise in the WMS. At the optimum total pressure for the detection of CO(2), N(2)O and CH(4), the limits of detection in the present system were determined.

Keywords: gas sensing; near-infrared absorption spectroscopy; wavelength modulation spectroscopy.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Carbon Dioxide / analysis
Computer Simulation
Gases / analysis*
Greenhouse Effect*
Lasers, Semiconductor*
Limit of Detection
Methane / analysis
Pressure
Spectroscopy, Near-Infrared / methods*

Substances

Gases
Carbon Dioxide
Methane