Testing angle independence of plasmonic metal coloration via FDTD

Angle-independent colors can be created on metals by exploiting plasmonic effects in arrangements of nanoparticles on the surface. We numerically demonstrate the angle-independence of the colors by using the Constant Transverse Wavenumber (CTW) technique implemented in the Finite-Difference Time-Domain (FDTD) method to simulate light reflection from a periodic array of nanoparticles under oblique incidence.