Coupled localized surface plasmon resonances in periodic arrays of gold nanowires on ion-exchange waveguide technology

Abstract

Coupled localized surface plasmon resonances (LSPRs) in periodic arrays of metallic nanowires are attractive for use in sensing applications due to their light enhancement and their sensitivity to the surrounding environment. Due to the interwire coupling, they behave as plasmonic waveguides with high wavevector modes that require bulky methods for efficient excitation. In this contribution, we demonstrate the excitation of coupled LSPRs in gold nanowires with photonic modes supported by an optical waveguide made with ion exchange technology. Currently, although weakly-coupled LSPRs are experimentally demonstrated, strongly-coupled LSPRs are only demonstrated numerically due to the challenge represented by the fabrication of a high density nanowire array with current electron beam lithography. Due to their operation across the visible spectrum and its low-loss coupling to standard optical fibers, integrated nanowires on glass waveguides open new perspectives for the development of hybrid photonic-plasmonic integrated optical devices.