Sensitive and selective detection of O H radicals using Faraday rotation spectroscopy at 2.8 μm

Weixiong Zhao (1, 2) , Gerard Wysocki (3) , Weidong Chen (1) , Eric Fertein (1) , David Le Coq (1) , Denis Petitprez (4) , Weijun Zhang (2)

1 LPCA - Laboratoire de Physico-Chimie de l'Atmosphère
2 Anhui Institute of Optics and Fine Mechanics
3 Princeton University
4 PhLAM - Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523

We report on the development of a Faraday rotation spectroscopy (FRS) instrument using a DFB diode laser operating at 2.8 μm for the hydroxyl (OH) free radical detection. The highest absorption line intensity and the largest gJ value make the Q (1.5) double lines of the 2∏3/2 state (ν = 1 ← 0) at 2.8 μm clearly the best choice for sensitive detection in the infrared region by FRS. The prototype instrument shows shot-noise dominated performance and, with an active optical pathlength of only 25 cm and a lock-in time constant 1E8 OH radicals/cm3

Mots clés: Spectrometers and spectroscopic instrumentation; Spectroscopy - modulation; Remote sensing and sensors

Domaines: Optique / photonique

Weixiong Zhao, Gerard Wysocki, Weidong Chen, Eric Fertein, David Le Coq, et al.. Sensitive and selective detection of O H radicals using Faraday rotation spectroscopy at 2.8 μm. Optics Express, 2011, 19 (3), pp.2493-2501. ⟨hal-01427541⟩