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Abstract: Hyperspectral Infrared Imaging of HF(v,J)Chemiluminescence and Gain in Chemically Reacting Flowfields
W.T. Rawlins, D.B. Oakes, S.J. Davis,
"Hyperspectral Infrared Imaging of HF(v,J)Chemiluminescence and Gain in Chemically Reacting Flowfields
,"
The Journal of Physical Chemistry A
111
(29)
, 6860-6869
(2007).
Copyright © 2007, American Chemical Society. All rights reserved.
This paper was published in Journal of Physical Chemistry A, Vol. 111, No. 29 2007 and is made available as an electronic abstract with the permission of the American Chemical Society. The full article is available for a fee from the Journal of Physical Chemistry A.
Abstract
This paper presents results from investigations of chemically reacting flowfields and optical gain profiles in HF chemical laser media by infrared hyperspectral imaging. Subsonic and supersonic chemiluminescent F + H2 reacting flowfields, produced in high-fluence microwavedriven reactors, were imaged at a series of wavelengths, 2.6 to 3.1 µm, by a low-order, spectrally scanning Fabry-Perot interferometer mated to an infrared camera. The resulting hyperspectral data cubes define the spectral and spatial distributions of the emission. Spectrally resolved images at high spatial resolution were processed to determine spatial distributions of the excited state concentrations of the product HF(v,J) molecules, as well as spatial distributions of smallsignal gain on specific laser transitions. Additional high-resolution Fourier transform spectroscopy and spectral fitting analysis determined detailed excited state distributions in the reacting flowfields. The measurements showed that energetic HF(v,J) state distributions were generated by both the supersonic and fast-flow subsonic mixing schemes. In particular, the subsonic reactor produced a spatially distributed field of inverted, near-nascent state populations, with small-signal gains near 2-3 %/cm.
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