Title

Near-IR absorption in high-purity photothermorefractive glass and holographic optical elements: measurement and application for high-energy lasers

Authors

Authors

J. Lumeau; L. Glebova;L. B. Glebov

Comments

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Abbreviated Journal Title

Appl. Optics

Keywords

INTERFEROMETER; CALORIMETER; IRRADIATION; Optics

Abstract

Volume Bragg gratings (VBGs) in photothermorefractive (PTR) glass are widely used for laser beam control including high-power laser systems. Among them, spectral beam combining based on VBGs is one of the most promising. Achieving 100 + kW of combined laser beams requires the development of PTR glass and VBGs with an extremely low absorption coefficient and therefore methods of its measurement. This paper describes the calorimetric method that was developed for measuring a low absorption coefficient in PTR glass and VBGs. It is based on transmission monitoring of the intrinsic Fabry-Perot interferometer produced by the plane-parallel surfaces of the measured optical elements when heated by high-power laser radiation. An absorption coefficient at 1085 nm as low as 5 x 10(-5) cm(-1) is demonstrated in pristine PTR glass while an absorption coefficient as low as 1 x 10(-4) cm(-1) is measured in high-efficiency reflecting Bragg gratings with highest purity. The actual level of absorption in PTR glass allows laser beam control at the 10 kW level, while the 100 kW level would require active cooling and/or decreasing the absorption in PTR Bragg gratings to a value similar to that in virgin PTR glass. (C) 2011 Optical Society of America

Journal Title

Applied Optics

Volume

50

Issue/Number

30

Publication Date

1-1-2011

Document Type

Article

Language

English

First Page

5905

Last Page

5911

WOS Identifier

WOS:000296555300018

ISSN

1559-128X

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