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Degradation Mechanisms In High Power Algaas Lasers

Wade C. Tang, Hal J. Rosen, Peter Vettiger and Dave J. Webb

As optical designs continually improve, limiting conditions on the image quality ultimately depend on the quality of the components. Surface roughness scatters light, reducing intensity and contrast. Quantitatively, optical surfaces can be evaluated using the bidirectional reflectance distribution function (BRDF). This statistical, Fourier-transform approach used to characterize surfaces gives an rms roughness of the surface. Quantifying contamination— dust particles on a mirror, for instance—is not nearly as well-developed.