title: Diode laser detection of greenhouse gases in the near-infrared region by wavelength modulation spectroscopy: pressure dependence of the detection sensitivity.
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.
authors.affiliation: 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
authors.forename: Takashi
authors.initials: T
authors.lastname: Asakawa
authors.forename: Nozomu
authors.initials: N
authors.lastname: Kanno
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tonokura
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis; D003198:Computer Simulation; D005740:Gases / Q000032:analysis*; D017752:Greenhouse Effect; D054023:Lasers, Semiconductor; D057230:Limit of Detection; D008697:Methane / Q000032:analysis; D011312:Pressure; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D005740:Gases; D002245:Carbon Dioxide; D008697:Methane