title: Ultrasensitive detection of nitric oxide at 5.33 microm by using external cavity quantum cascade laser-based Faraday rotation spectroscopy.
abstract: A transportable prototype Faraday rotation spectroscopic system based on a tunable external cavity quantum cascade laser has been developed for ultrasensitive detection of nitric oxide (NO). A broadly tunable laser source allows targeting the optimum Q(3/2)(3/2) molecular transition at 1875.81 cm(-1) of the NO fundamental band. For an active optical path of 44 cm and 1-s lock-in time constant minimum NO detection limits (1sigma) of 4.3 parts per billion by volume (ppbv) and 0.38 ppbv are obtained by using a thermoelectrically cooled mercury-cadmium-telluride photodetector and liquid nitrogen-cooled indium-antimonide photodetector, respectively. Laboratory performance evaluation and results of continuous, unattended monitoring of atmospheric NO concentration levels are reported.
authors.affiliation: Rice Quantum Institute, Rice University, 6100 Main Street, Houston, TX 77005, USA.
authors.forename: Rafal
authors.initials: R
authors.lastname: Lewicki
authors.forename: James H
authors.initials: JH
authors.lastname: Doty
authors.forename: Robert F
authors.initials: RF
authors.lastname: Curl
authors.forename: Frank K
authors.initials: FK
authors.lastname: Tittel
authors.forename: Gerard
authors.initials: G
authors.lastname: Wysocki
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D007834:Lasers; D008280:Magnetics; D009569:Nitric Oxide / Q000032:analysis*; D011789:Quantum Theory; D012399:Rotation; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D009569:Nitric Oxide