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Proceedings Paper

Mode Medium Interaction In Continuous Wave (CW) Flowing Gas Lasers
Author(s): E. R. Peressini; C. G. Parazzoli
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Paper Abstract

A general nonlinear treatment of mode medium interaction in CW flowing gas lasers is presented. Mode medium interaction is the term which has been used to refer to the dynamic process of extracting optical energy from an excited laser medium. The nonlinear theory describes the coupling between the excited medium perturbation due to optical power extraction and the optical system controlling the power extraction. The nonlinear theory shows that, while a significant mode medium interaction can exist in large scale devices, no acoustic instability is predicted. This prediction is contrasted with results obtained from a conventional linear instability analysis of the same system which erroneously suggests an acoustic instability such that beyond a small threshold value, medium and optical power disturbances are amplified to instability. The underlying reasons for the breakdown of the linearized theory are described. Scaling relations developed from the nonlinear theory are also presented to establish that high quality large scale CW flowing gas lasers are feasible. The paper is theoretically oriented; however, some supporting experimental data is presented. In addition to the nonlinear stability analysis, an accurate description of cross-flow medium acoustics is developed, which properly accounts for the bulk heat input into the flowing medium. It is shown that the pressure gradient, produced in the flow direction by the medium bulk heating, strongly damps the buildup of cross-flow acoustic disturbances.

Paper Details

Date Published: 17 August 1978
PDF: 13 pages
Proc. SPIE 0138, Advances in Laser Technology III: Emphasizing Gaseous Lasers, (17 August 1978); doi: 10.1117/12.956226
Show Author Affiliations
E. R. Peressini, Hughes Aircraft Company (United States)
C. G. Parazzoli, Hughes Aircraft Company (United States)

Published in SPIE Proceedings Vol. 0138:
Advances in Laser Technology III: Emphasizing Gaseous Lasers
David Finkleman; Joseph Stregack, Editor(s)

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