Author(s): Uday Bhaskar P, P Vinodh Kumar, NL Durga Prasad, P Mukharji and I Sudheer Babu
length, multicomponent CRD S gas sensor operating on the basis of a compact
photonic crystal fibre
super continuum lig ht source has been constructed. It features a simple desig n 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 capabili ty 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 sig nal-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 multi wave length CRD S techniq ues is also given.