title: Development of an automated diode-laser-based multicomponent gas sensor.
abstract: The implementation and application of a portable fiber-coupled trace-gas sensor for the detection of several trace gases, including CO2, CH4, and H2CO, are reported. This particular sensor is based on a cw fiber-amplified near-infrared (distributed Bragg reflector) diode laser and an external cavity diode laser that are frequency converted in a periodically poled lithium niobate crystal to the mid-IR spectroscopic fingerprint region (3.3-4.4 micrometers). A continuous absorption spectrum of CH4 and H2CO from 3.37 to 3.10 micrometers with a spectral resolution of 40 MHz (approximately 0.0013 cm-1) demonstrated the spectral performance that can be achieved by means of automated wavelength tuning and phase matching with stepper motor control. Autonomous long-term detection of ambient CO2 and CH4 over a 3- and 7-day period was also demonstrated.
authors.affiliation: Rice Quantum Institute, Rice University, Houston, Texas 77251-1892, USA.
authors.forename: D
authors.initials: D
authors.lastname: Richter
authors.forename: D G
authors.initials: DG
authors.lastname: Lancaster
authors.forename: F K
authors.initials: FK
authors.lastname: Tittel
mesh_terms: D001331:Automation; D002245:Carbon Dioxide / Q000032:analysis; D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D005069:Evaluation Studies as Topic; D005336:Fiber Optic Technology; D005557:Formaldehyde / Q000032:analysis; D005740:Gases / Q000032:analysis*; D007834:Lasers; D008697:Methane / Q000032:analysis; D013055:Spectrophotometry, Infrared / Q000295:instrumentation*
chemical_list: D005740:Gases; D002245:Carbon Dioxide; D005557:Formaldehyde; D008697:Methane