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Proceedings Paper

Thermal Shock: Catastrophic Damage To Transmassive Optical Components In High Power Continous Wave And Repetitive Pulsed Laser Environment
Author(s): J R Palmer
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Paper Abstract

The direction of this paper is to set out the analytical expressions which may be used to approximate the maximum flux density, or fluence, which will be required to cause thermal shock catastrophic damage to various and sundry transmissive optical components. The equations will describe the temperature, and subsequent stress gradients that are engendered, to cause the transmissive optic to reach the Modulus of Rupture and, self destruct in tension. Because of the nature of absorption on the surface, vis-a-vis, the bulk absorption, the surfaces of transmissive optics are very susceptible to substantial thermal gradients. The absorption on the surfaces of optics has been shown to be several times to hundreds of times greater than the bulk. If the optics are of the production line type, the absorption can be expected to be substantially more than those optics which are prepared for use in the laboratory environment Assembly line manufactured optics appear to be more greatly affected by defects, scratches, and residues which lead to greater surface absorption and are, subsequently, more susceptible to thermal shock catastrophic damage. We will look at the impact of Continuous Wave, Single Pulse, and Repetitive Pulsed laser environments on an optic which is transparent at some wavelengths, and not transparent at others. We will look at the equations that describe the temperature gradients developed in real time for both the non-transparent and transparent case. Damage flux density, and fluence thresholds are provided for a number of common materials used for windows and domes on optical systems that have no forced or free convection and those that are used in high velocity flow, forced convection, environments.

Paper Details

Date Published: 11 July 1989
PDF: 54 pages
Proc. SPIE 1047, Mirrors and Windows for High Power/High Energy Laser Systems, (11 July 1989); doi: 10.1117/12.951354
Show Author Affiliations
J R Palmer, University Of Alabama (United States)


Published in SPIE Proceedings Vol. 1047:
Mirrors and Windows for High Power/High Energy Laser Systems
Claude A. Klein, Editor(s)

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