Characterization of Absorption Losses and Transient Thermo-Optic Effects in a High-Power Laser System

(1) Background: The modeling, characterization, and mitigation of transient lasers, thermal stress, and thermo-optic effects (TOEs) occurring inside high energy lasers have become hot research topics in laser physics over the past few decades. The physical sources of TOEs are the un-avoidable residu...

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Published inPhotonics Vol. 7; no. 4; p. 94
Main Authors Gorajek, Lukasz, Gontar, Przemyslaw, Jabczynski, Jan, Firak, Jozef, Stefaniak, Marek, Dabrowski, Miroslaw, Orzanowski, Tomasz, Trzaskawka, Piotr, Sosnowski, Tomasz, Firmanty, Krzysztof, Miczuga, Marcin, Barela, Jaroslaw, Kopczynski, Krzysztof
Format Journal Article
LanguageEnglish
Published MDPI AG 01.12.2020
Subjects
absorption losses
high-power lasers
laser weapon
optical technology
thermal imaging
thermal optics
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Summary:(1) Background: The modeling, characterization, and mitigation of transient lasers, thermal stress, and thermo-optic effects (TOEs) occurring inside high energy lasers have become hot research topics in laser physics over the past few decades. The physical sources of TOEs are the un-avoidable residual absorption and scattering in the volume and on the surface of passive and active laser elements. Therefore, it is necessary to characterize and mitigate these effects in real laser systems under high-power operations. (2) Methods: The laboratory setup comprised a 10-kW continuous wave laser source with a changeable beam diameter, and dynamic registration of the transient temperature profiles was applied using an infrared camera. Modeling using COMSOL Multiphysics enabled matching of the surface and volume absorption coefficients to the experimental data of the temperature profiles. The beam quality was estimated from the known optical path differences (OPDs) occurring within the examined sample. (3) Results: The absorption loss coefficients of dielectric coatings were determined for the evaluation of several coating technologies. Additionally, OPDs for typical transmissive and reflective elements were determined. (4) Conclusions: The idea of dynamic self-compensation of transient TOEs using a tailored design of the considered transmissive and reflecting elements is proposed.
ISSN:2304-6732
2304-6732
DOI:10.3390/photonics7040094