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Proceedings Paper

Detailed investigation of the molecular kinetics in the active medium of a dc-excited fast-axial-flow CO2 laser using a high-resolution mid-IR spectrometer
Author(s): David J. Toebaert; Maxim Spiridonov; Peter F. Muys; E. Desoppere
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Paper Abstract

A 4.5 micrometer tunable-diode laser based molecular absorption spectrometer is used to investigate the rovibrational level populations in a fast-flowing He/N2/CO2 gas discharge. The variation of the rovibrational temperatures is determined over a wide range of discharge parameters relevant for laser action. Good agreement is obtained with a previously developed fully three-dimensional model of the gas flow and vibrational kinetics in non-lasing conditions. The main assumption of the three-temperature model, the near-coincidence of carbon dioxide bending mode temperature and rotational temperature is shown to hold true. In a next step the radial distribution of the vibrational energy is investigated for two different gas inlet sections. The inadequacy of visual observation of the side-light emission is demonstrated and design considerations are formulated. Finally the rovibrational temperatures are measured under lasing conditions, for two different output coupler reflectivities. A maximum electro-optic efficiency of 26% is reached at a carbon dioxide asymmetrical stretch mode temperature reduced to 900 K. Preliminary tests using the same spectrometer of a novel catalyst for CO recombination are reported and an efficiency of 21% is demonstrated under sealed-off operating conditions.

Paper Details

Date Published: 3 March 1997
PDF: 6 pages
Proc. SPIE 3090, 12th Symposium and School on High-Resolution Molecular Spectroscopy, (3 March 1997); doi: 10.1117/12.267771
Show Author Affiliations
David J. Toebaert, Univ. of Gent (Belgium)
Maxim Spiridonov, General Physics Institute (Russia)
Peter F. Muys, Radius Engineering NV (Belgium)
E. Desoppere, Univ. of Gent (Belgium)


Published in SPIE Proceedings Vol. 3090:
12th Symposium and School on High-Resolution Molecular Spectroscopy

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