Figure 2.

Optical response of the bare FS substrate, flat (continuous) polyimide (flat PI), and nanostructured polyimide (Nanostructured PI) on the same substrate. Measured direct transmission (a) and reflection (b) for the different structures. Experiment (continuous line) and simulation (dashed line). Note that only the front side is coated with PI and nanostructured PI. The inset shows a schematic view of the propagation of light rays through the nanostructured PI. The antireflective effect comes from the destructive interference created by the film, approximating a quarter-wave layer.