Paper
5 August 1980 Mirrors And Windows In Power Optics
Claude A. Klein
Author Affiliations +
Proceedings Volume 0216, Optics in Adverse Environments II; (1980) https://doi.org/10.1117/12.958463
Event: 1980 Los Angeles Technical Symposium, 1980, Los Angeles, United States
Abstract
High-energy laser (HEL) systems involve an optical train consisting of mirrors and windows, which may compromise the system's operation because of unavoidable irradiance-mapping aberrations resulting from the absorption of some fraction of the incident laser-beam energy. This paper describes an analytic investigation of relevant processes and discusses how laser-driven mirror/window distortions may affect the performance of HEL systems with regard to focal intensities and on-target fluences. An approximate expression for the brightness at the Gaussian focus is derived on the basis of the AFWL far-field degradation model and shown to be simple enough to allow HEL system designers to assess the capability of a contemplated optical train and to evaluate its behavior as a function of beam-power level and laser run-time. Two figures of merit are introduced for the purpose of characterizing the response of power-optics mirrors and windows in terms of thermally induced wavefront errors. On using these figures of merit (FoMm and FoMw), an important result emerges: If the window-pane and the mirror-faceplate material both have positive distortion coefficients, window lensing suppresses the steady-state mirror-related phase aberration at time tc = N (D /d)2 FoMW/FoMM, where N is the number of relay mirrors and D /d is the telescope magnification. In applying these considerations to a model system operating at chemical laser wavelengths, we find that CVD-ZnSe output windows can be quite beneficial in maximizing either the peak irradiance on target or the short-pulse energy delivery capability of contemporary HEL systems.
© (1980) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Claude A. Klein "Mirrors And Windows In Power Optics", Proc. SPIE 0216, Optics in Adverse Environments II, (5 August 1980); https://doi.org/10.1117/12.958463
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KEYWORDS
Mirrors

Systems modeling

Near field optics

Thermography

Wavefronts

Absorption

Relays

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