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Refractive screen. (a) Detail with holes are on 15-μm centers. (b) Detail of the antireflection coating, drawn to scale. The silicon nitride core with n = 2 shown in darker gray has thickness of 97,367 and 637 nm. The inner coating has index 1.587 and thickness 94 nm (medium gray), and the outer index is 1.26 and thickness 119 nm (light gray).
