Detection of N2O by photoacoustic spectroscopy with a compact, pulsed optical parametric oscillator

A pulsed optical parametric oscillator (OPO) operated in an optical cavity with a grazing-incidence grating configuration (GIOPO) was used for sensitive photoacoustic detection of trace quantities of dinitrogen oxide (N₂O). The (ν₁+ν₃) combination vibration band of N₂O was excited with the idler beam of the GIOPO at 2.86 μm using an optical cavity optimized for the idler beam. The linewidth of the GIOPO could be reduced to 0.4 cm^-1, allowing the rotational structure of the absorption spectrum to be resolved. A concentration sensitivity (signal-to-noise ratio=3) of 60 parts in 10⁹ by volume (60 ppb V) N₂O in synthetic air was obtained. This may be sufficient for continuous monitoring of N₂O in the atmosphere. Received: 29 April 2002 / Revised version: 4 June 2002 / Published online: 21 August 2002 RID="*" ID="*"Corresponding author. Fax: +49-6221/54-4255, E-mail: peter.hess@urz.uni-heidelberg.de