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Proceedings Paper

Ellipsoidal diffraction grating as output coupler for quasi-optical gyrotrons
Author(s): J. P. Hogge
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Paper Abstract

The use of a diffraction grating arranged in the -1 Littrow mount as an output coupler for a quasi-optical Fabry-Pérot resonator at microwave frequencies (100 GHz) was suggested in 1990 [1]. A planar grating with curvilinear grooves (in order to match the Littrow condition everywhere on the surface for a given Gaussian beam) gives a power coupling efficiency of 85%, which is limited by the depolarization induced by the curvature of the grooves. An ellipsoidal grating with linear, equidistant grooves minimized the depolarization but gave approximately the same global efficiency because of distortion. We report low power tests on an improvement of the second scheme, based on curved grooves on an ellipsoidal surface, which gives a global efficiency of 94%.

Paper Details

Date Published: 4 December 2017
PDF: 2 pages
Proc. SPIE 1576, 16th International Conference on Infrared and Millimeter Waves, 15767M (4 December 2017); doi: 10.1117/12.2297987
Show Author Affiliations
J. P. Hogge, Ecole Polytechnique Fédérale de Lausanne (Switzerland)

Published in SPIE Proceedings Vol. 1576:
16th International Conference on Infrared and Millimeter Waves
Minh Quang Tran, Editor(s)

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