Figure 3.

(a) SEM image of surface patterning, which is present on both sides of the substrate. (b) Imaging test of the fabricated optic taken on an FLIR BOSON+ thermal camera. Borders to the patterned region and wafer edge have been added for clarity. Si transmission improvement is immediately noticeable compared to unpatterned edges of wafer and compares favorably with the Ge window on the left. (c) Comparison of unpatterned (black) and patterned (blue) intrinsic Si and AR coated Ge (yellow) windows at 0° incidence. Patterning results in an up to 40% increase in transmission over the bare case. (d) Angular falloff plot showing integrated spectral transmission over the 7–14 μm band for bare Si, BBAR coated Ge window, and Mie patterned Si.