Guidelines for designing 2D and 3D plasmonic stub resonators

TL;DR

This paper compares 2D and 3D plasmonic stub resonators, extending scattering matrix theory to guide their design, and verifies the results with FDTD simulations, highlighting the effects of radiation loss and improved terminations.

Contribution

It extends scattering matrix theory to 3D plasmonic resonators and provides design guidelines for their spectral response, validated by FDTD simulations.

Findings

Scattering matrix theory can be applied to 3D devices.

Design maps for stub lengths determine spectral features.

Improved waveguide terminations enhance resonator performance.

Abstract

In this work, we compare the performance of plasmonic waveguide integrated stub resonators based on 2D metal-dielectric-metal and 3D slot waveguide (SWG) geometries. We show that scattering matrix theory can be extended to 3D devices, and by employing scattering matrix theory, we provide the guidelines for designing plasmonic 2D and 3D single-stub and double-stub resonators with a desired spectral response at the design wavelength. We provide transmission maps of 2D and 3D double-stub resonators versus stub lengths, and we specify the different regions on these maps that result in a minimum, a maximum, or a plasmonically induced transparency shape in the transmission spectrum. Radiation loss from waveguide terminations leads to a degradation of the 3D SWG-based resonators. We illustrate improved waveguide terminations that boost resonator properties. We verify our results with 3D finite-difference time-domain (FDTD) simulations.