A transportable spectrometer for in situ and local measurements of iodine monoxide at mixing ratios in the 10-14 range

Guillaume Méjean (1) , Roberto Grilli (1) , Chadi Abd Alrahman (1) , Irène Ventrillard (1) , Samir Kassi (1) , Daniele Romanini (1)

1 LAME-LIPhy - LAsers, Molécules et Environnement

We present a robust, compact, and transportable instrument that measures the iodine monoxide atmospheric radical at extremely low concentration, down to 40 ppqv (parts per quadrillion by volume, 1:1015). As nitrogen dioxide is strongly absorbed in the same spectral region it could be simultaneously measured down to 4 pptv (parts per trillion by volume, 1:1012). Relying on ''mode locked cavity-enhanced absorption spectroscopy,'' the instrument makes use of a free-running commercial femtosecond Titane Saphir laser. We demonstrate that this multiplex detection scheme provides shot noise limited spectra for acquisition times as long as 5 min. Moreover, this instrument is very versatile as it can be potentially tuned from the infrared to the ultraviolet (1080-340 nm) to reach various molecular absorptions. It has been recently deployed at the Station Biologique de Roscoff on the North West Atlantic coast of France.

Mots clés: chemical variables measurement; gas sensors; infrared spectra; measurement by laser beam; shot noise; ultraviolet spectra; ultraviolet spectrometers; Sensors; remote sensing; Lasers; Metrological applications; optical frequency synthesizers for precision spectroscopy; Chemical analysis and related physical methods of analysis

Domaines: Optique [physics.optics]

Guillaume Méjean, Roberto Grilli, Chadi Abd Alrahman, Irène Ventrillard, Samir Kassi, et al.. A transportable spectrometer for in situ and local measurements of iodine monoxide at mixing ratios in the 10-14 range. Applied Physics Letters, 2012, 100, pp.1110. ⟨10.1063/1.4726190⟩. ⟨hal-00996499⟩