Scattering of a plasmonic nanoantenna embedded in a silicon waveguide

TL;DR

This paper presents a theoretical study of a silicon waveguide integrated with a gold nanoantenna, demonstrating resonance-driven filtering with significant transmission suppression and potential for integrated optoelectronic circuits.

Contribution

It introduces a hybrid silicon-metallic system with analytical and numerical analysis of resonance effects, showing effective control of light signals in integrated photonic devices.

Findings

85% transmission drop at resonance frequency

Three times more scattering than absorption

Feasible fabrication with standard lithography methods

Abstract

Plasmonic antennas integrated on silicon devices have large and yet unexplored potential for controlling and routing light signals. Here, we present theoretical calculations of a hybrid silicon-metallic system in which a single gold nanoantenna embedded in a single-mode silicon waveguide acts as a resonance-driven filter. As a consequence of scattering and interference, when the resonance condition of the antenna is met, the transmission drops by 85% in the resonant frequency band. Firstly, we study analytically the interaction between the propagating mode and the antenna by including radiative corrections to the scattering process and the polarization of the waveguide walls. Secondly, we find the configuration of maximum interaction and numerically simulate a realistic nanoantenna in a silicon waveguide. The numerical calculations show a large suppression of transmission and three times more scattering than absorption, consequent with the analytical model. The system we propose can be easily fabricated by standard silicon and plasmonic lithographic methods, making it promising as real component in future optoelectronic circuits.