title: Application of a broadband blue laser diode to trace NO2 detection using off-beam quartz-enhanced photoacoustic spectroscopy.
abstract: We applied for the first time, to our knowledge, broadband off-beam quartz-enhanced photoacoustic spectroscopy (BB-OB-QEPAS) to trace NO2 detection using a broadband blue laser diode centered at 450 nm. A detection limit of 18 ppbv (parts in 10(9) by volume) for NO2 in N2 at atmospheric pressure was achieved with an average laser power of 7 mW at a 1 s integration time, which corresponds to a 1 σ normalized noise equivalent absorption coefficient of 4.1×10(-9)  cm(-1) W=Hz(1=2). An Allan variance analysis was performed to investigate the long-term stability of the BB-OB-QEPAS-based NO2 sensor.
authors.affiliation: Key Laboratory of Atmospheric Composition and Optical Radiation, Chinese Academy of Sciences, Hefei, China.
authors.forename: Hongming
authors.initials: H
authors.lastname: Yi
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.forename: Weidong
authors.initials: W
authors.lastname: Chen
authors.forename: Tu
authors.initials: T
authors.lastname: Tan
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Gao