title: Application of a widely electrically tunable diode laser to chemical gas sensing with quartz-enhanced photoacoustic spectroscopy.
abstract: A near-infrared diode laser with sample-grating distributed Bragg reflectors was used as a widely tunable spectroscopic source for multispecies chemical sensing. Quartz-enhanced photoacoustic spectroscopy was utilized to obtain high absorption sensitivity in a compact gas cell. CO2, H2O C2H2, and NH3 were monitored. A noise equivalent sensitivity of 8 x 10(-9) cm(-1) W(-1) Hz(-1/2)for NH3 detection was achieved, which corresponds to a NH3 mixing ratio of 4.4 parts in 10(6) by volume (ppmv) with a 1-s time constant and available 5.2-mW optical power in the gas cell.
authors.affiliation: Rice Quantum Institute, Rice University, Houston, Texas 77251-1892, USA. weidmann@rice.edu
authors.forename: Damien
authors.initials: D
authors.lastname: Weidmann
authors.forename: Anatoliy A
authors.initials: AA
authors.lastname: Kosterev
authors.forename: Frank K
authors.initials: FK
authors.lastname: Tittel
authors.forename: Neil
authors.initials: N
authors.lastname: Ryan
authors.forename: David
authors.initials: D
authors.lastname: McDonald