Title

Near-Ir Absorption In High-Purity Photothermorefractive Glass And Holographic Optical Elements: Measurement And Application For High-Energy Lasers

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 1085nm as low as 5 × 10?5 cm?1 is demonstrated in pristine PTR glass while an absorption coefficient as low as 1 × 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 10kW level, while the 100kW level would require active cooling and/or decreasing the absorption in PTR Bragg gratings to a value similar to that in virgin PTR glass. © 2011 Optical Society of America.

Publication Date

10-20-2011

Publication Title

Applied Optics

Volume

50

Issue

30

Number of Pages

5905-5911

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1364/AO.50.005905

Socpus ID

80054985237 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/80054985237

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