PCF-based cavity enhanced spectroscopic sensors for simultaneous multicomponent trace gas analysis.
A multiwavelength, multicomponent CRDS gas sensor operating on the basis of a compact photonic crystal fibre supercontinuum light source has been constructed. It features a simple design encompassing one radiation source, one cavity and one detection unit (a spectrograph with a fitted ICCD camera) that are common for all wavelengths. Multicomponent detection capability of the device is demonstrated by simultaneous measurements of the absorption spectra of molecular oxygen (spin-forbidden b-X branch) and water vapor (polyads 4v, 4v + δ) in ambient atmospheric air. Issues related to multimodal cavity excitation, as well as to obtaining the best signal-to-noise ratio are discussed together with methods for their practical resolution based on operating the cavity in a "quasi continuum" mode and setting long camera gate widths, respectively. A comprehensive review of multiwavelength CRDS techniques is also given.
Institute of Experimental Physics, Free University of Berlin, Arnimallee 14, 14195 Berlin, Germany. walternak@usp.br
Walter M
WM
Nakaema
Zuo-Qiang
ZQ
Hao
Philipp
P
Rohwetter
Ludger
L
Wöste
Kamil
K
Stelmaszczyk
D000042:Absorption; D003460:Crystallization; D005740:Gases / Q000032:analysis*; D055620:Optical Phenomena; D055095:Optics and Photonics / Q000295:instrumentation*; D013057:Spectrum Analysis / Q000295:instrumentation*; D014867:Water / Q000737:chemistry
D005740:Gases; D014867:Water