31 March 1995 Interaction of pulsed CO2 laser radiation with optical materials
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Proceedings Volume 2502, Gas Flow and Chemical Lasers: Tenth International Symposium; (1995); doi: 10.1117/12.204890
Event: Gas Flow and Chemical Lasers: Tenth International Symposium, 1994, Friedrichshafen, Germany
Abstract
Pulsed high power CO2-laser irradiation can cause damage to optical materials. Some results obtained at ISL with a repetitively pulsed CO2-laser with pulse energies up to 24 J are presented in this paper. In production facilities with CO2-lasers, optics transmitting in the visible spectral range like glass or PMMA are used as protection windows against scattered light. These materials have small skin depths for electromagnetic waves at 10,6 micrometers , typically in the order of some micrometers , so the interaction takes place in thin surface layers. Under high power laser radiation the transparency of the optics is lowered. On the other hand infrared transmitting optics like KCl or ZnSe show a low intrinsic absorption for CO2-laser radiation. Theoretical estimations matching with the experimental observations showed, however, that strong heating occurs, if a thin layer of inhomogeneities, typically some micrometers thick, is included in the surrounding material with slightly higher absorption than the surrounding lowless material. Under these assumptions the thermally induced stress inside the materials can explain the experimentally observed mechanical damage. Besides these thermal damage effects mechanical momenta are transferred by pulsed laser radiation to the optics. Experimental results as obtained by a ballistic pendulum are reported.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ruediger Schmitt, Manfred Hugenschmidt, L. Geiss, E. Stechele, "Interaction of pulsed CO2 laser radiation with optical materials", Proc. SPIE 2502, Gas Flow and Chemical Lasers: Tenth International Symposium, (31 March 1995); doi: 10.1117/12.204890; https://doi.org/10.1117/12.204890
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KEYWORDS
Absorption

Polymethylmethacrylate

Glasses

Carbon dioxide lasers

Tissue optics

Pulsed laser operation

Thermography

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