Plasmonic sensors based on funneling light through nanophotonic structures

TL;DR

This paper introduces a novel plasmonic refractometric sensor using metallic gratings with funneling light to detect changes in analyte refractive index, suitable for biomedical applications.

Contribution

It proposes a new sensor design with two configurations that enhance light confinement and resonance sensitivity for refractive index sensing.

Findings

Both designs exhibit narrow spectral features sensitive to refractive index changes.

The structures effectively detect biomedical sample variations.

Funneling mechanisms improve light confinement and sensor performance.

Abstract

We present a refractometric sensor realized as a stack of metallic gratings with subwavelength features and embedded within a low-index dielectric medium. Light is strongly confined through funneling mechanisms and excites resonances that sense the analyte medium. Two terminations of the structure are compared. One of them has a dielectric medium in contact with the analyte and exploits the selective spectral transmission of the structure. The other design has a metallic continuous layer that generates surface plasmon resonances at the metal/analyte interface. Both designs respond with narrow spectral features that are sensible to the change in the refractive index of the analyte and can be used for sensing biomedical samples.