Hyper-doped silicon nanoantennas and metasurfaces for tunable infrared\n plasmonics

Abstract

We present the experimental realization of ordered arrays of hyper-doped\nsilicon nanodisks, which exhibit a localized surface plasmon resonance. The\nplasmon is widely tunable in a spectral window between 2 and 5 $\\mu$m by\nadjusting the free carrier concentration between 10$^{20}$ and 10$^{21}$\ncm$^{-3}$. We show that strong infrared light absorption can be achieved with\nall-silicon plasmonic metasurfaces employing nano-structures with dimensions as\nlow as 100\\,nm in diameter and 23 nm in height. Our numerical simulations show\nan excellent agreement with the experimental data and provide physical insights\non the impact of the nanostructure shape as well as of near-field effects on\nthe optical properties of the metasurface. Our results open highly promising\nperspectives for integrated all-silicon-based plasmonic devices for instance\nfor chemical or biological sensing or for thermal imaging.\n