title: Near-infrared diode laser based spectroscopic detection of ammonia: a comparative study of photoacoustic and direct optical absorption methods.
abstract: A photoacoustic spectroscopic (PAS) and a direct optical absorption spectroscopic (OAS) gas sensor, both using continuous-wave room-temperature diode lasers operating at 1531.8 nm, were compared on the basis of ammonia detection. Excellent linear correlation between the detector signals of the two systems was found. Although the physical properties and the mode of operation of both sensors were significantly different, their performances were found to be remarkably similar, with a sub-ppm level minimum detectable concentration of ammonia and a fast response time in the range of a few minutes.
authors.affiliation: Research Group on Laser Physics of the Hungarian Academy of Sciences, Szeged, Hungary.
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Bozoki
authors.forename: Arpad
authors.initials: A
authors.lastname: Mohacsi
authors.forename: Gabor
authors.initials: G
authors.lastname: Szabo
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Bor
authors.forename: Miklos
authors.initials: M
authors.lastname: Erdelyi
authors.forename: Weidong
authors.initials: W
authors.lastname: Chen
authors.forename: Frank K
authors.initials: FK
authors.lastname: Tittel
mesh_terms: D000162:Acoustics; D000641:Ammonia / Q000032:analysis*; D002138:Calibration; D004784:Environmental Monitoring / Q000379:methods*; D007834:Lasers; D055095:Optics and Photonics; D019265:Spectroscopy, Near-Infrared / Q000379:methods*
chemical_list: D000641:Ammonia