Fig. 3: Pixel-to-pixel variation in diffraction.
From: Covert infrared image encoding through imprinted plasmonic cavities
The spectral and order averaged diffraction efficiency of the first and second orders at normal incidence for a the MWIR device and b LWIR device. Efficiency is averaged over the visible spectral range of 400–800 nm. Black dotted lines indicate the range of diameters with a maximum deviation of 1%. Insets depict the respective devices and the degeneracy of the first diffracted order based on the symmetry of the hole array
