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Proceedings Paper

Power extraction investigations for a 10-kW-class supersonic COIL
Author(s): Juergen Handke; Karin M. Gruenewald; Wolfgang O. Schall; Lutz v. Entress-Fuersteneck
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Paper Abstract

In a stable resonator configuration, the output power and the power density distribution of a chemical oxygen-iodine laser (COIL) were measured for various outcoupling geometries: Diaphragms with slit apertures of various size were introduced intracavity in front of the outcoupling mirror. The slit was placed at different positions along the flow axis. Furthermore, outcoupling mirrors of various reflectivity were used. For all experimental conditions the measured power density distribution at the outcoupling mirror reveals strong symmetry effects: The beam patterns are always symmetric to the resonator axis. The beam shape and the beam size are defined by the hardware aperture that is nearest to the resonator axis. As a function of the slit width, the laser output power saturates well before the aperture of the resonator is fully opened. Fifty percent of the maximum output power were achieved at a width of 6 mm only. Good agreement is found between the measured data and theoretical calculations, when taking into account the specific flow conditions. The data highlight the significance of deactivation processes and the strong iodine repumping mechanism within the cavity. For standard operating conditions a Rigrod type analysis reveals a small signal gain that is nearly constant throughout the cavity exceeding 1.3% cm-1. The outcoupling reflectivity for the maximum power output was found at a value of about 94%. These experimental data agree well with a simplified analytic model for gain saturation and power extraction as derived by G. D. Hager et al.

Paper Details

Date Published: 22 December 1998
PDF: 6 pages
Proc. SPIE 3574, XII International Symposium on Gas Flow and Chemical Lasers and High-Power Laser Conference, (22 December 1998); doi: 10.1117/12.334449
Show Author Affiliations
Juergen Handke, DLR Institut fuer Technische Physik (Germany)
Karin M. Gruenewald, DLR Institut fuer Technische Physik (Germany)
Wolfgang O. Schall, DLR Institut fuer Technische Physik (Germany)
Lutz v. Entress-Fuersteneck, DLR Raumfahrtantriebe (Germany)

Published in SPIE Proceedings Vol. 3574:
XII International Symposium on Gas Flow and Chemical Lasers and High-Power Laser Conference
Anatoly S. Boreisho; Gennady A. Baranov, Editor(s)

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