Optical switching in graded plasmonic waveguides

TL;DR

This paper proposes a novel optical switching mechanism using graded plasmonic waveguides, enabling tunable control of light transmission through nanoparticle chains embedded in variable dielectric media.

Contribution

It introduces a new confinement mechanism in plasmonic waveguides and demonstrates tunability of optical transmission via refractive index and nanoparticle spacing.

Findings

Passband tunability achieved by nanoparticle spacing

Refractive index modulation controls optical transmission

Numerical calculations confirm theoretical predictions

Abstract

A new mechanism of longitudinal confinement of optical energy via coupled plasmon modes is proposed in chains of noble metal nanoparticles embedded in a graded dielectric medium, which is analogous to the confinement of electrons in semiconductor quantum wells. In these systems, one can control the transmission of optical energy by varying the graded refractive index of the host medium or the separation between the nanoparticles to realize the photonic analogue of electronic transistors. Possible passband tunability by nanoparticle spacing and modulation of the refractive index in the host medium have been presented explicitly and compared favorably with numerical calculations.