Design and optimization of ultrathin spectral filters based on silicon nanocross antenna arrays

Plasmonic nanoantenna arrays have been investigated in connection with spectral filtering applications in the last decade. We show that an all-dielectric nanoantenna can also perform a similar function. We propose a nanocross-shaped nanoantenna array design and present a numerical study of spectral filters based on this design. A broad gamut of colors is achievable in both the reflective and transmissive modes and is reasonably robust to fabrication-related imperfections. These all-dielectric ultrathin spectral filters are promising for the realization of multispectral image sensors and low-power displays.