Fig. 1: Optical design and simulation of three-channel, two-dimensional, anti-Hermitian PIN Si metasurface.
From: Subwavelength pixelated CMOS color sensors based on anti-Hermitian metasurface
a Top- and b side-view schematic of 3-color, 2-D array of silicon nanocylinders. c, e Simulated absorption spectra of normally incident light in green-, yellow-, and red-absorbing nanocylinders for lattice constants of c 350 nm, mixed coupling condition, and e 220 nm, anti-Hermitian coupling condition. d, f Simulated dissipated power in each nanocylinder at the associated wavelength of peak absorption (590, 610, and 640 nm in d and 575, 590, and 625 nm in f). It can be seen that when the lattice constant is above the anti-Hermitian regime, the three-color spectra are broad and overlapping, leading to optical color crosstalk between three-color channels. The optimal structure designed by the principle of anti-Hermitian coupling has enhanced quality factors, leading to a significant reduction of color crosstalk and improvement of the peak absorption efficiency. Source data for c and e are available in the Source Data File tabs labeled 1c and e, respectively.
