Ultracompact high-contrast magneto-optical disk resonator side-coupled to a plasmonic waveguide and switchable by an external magnetic field

TL;DR

This paper introduces a novel magneto-optical disk resonator coupled with a plasmonic waveguide, enabling high-contrast, reversible switching of surface plasmon polaritons via an external magnetic field, with significant modulation enhancement.

Contribution

It presents a new ultra-small magneto-optical disk resonator design that achieves high-contrast modulation and reversible switching of surface plasmon modes.

Findings

Modulation contrast ratio exceeds 90% within hundreds of GHz bandwidth.

Magneto-plasmonic modulation is enhanced over 200 times.

Reversible on/off switching of SPP modes demonstrated by magnetic field reversal.

Abstract

Here we propose and study a novel type of plasmonic resonators based on a metal-insulator-metal waveguide and a side-coupled magneto-optical disk controlled by an external magnetic field. The wavenumber change and the transmission of surface-plasmon-polaritons (SPPs) can be tuned by altering the magnetic field and reversible on/off switching of the running SPP modes by a reversal of the direction of the external magnetic field is demonstrated. Resonant enhancement of the magneto-plasmonic modulation by more than 200 times leads to a modulation contrast ratio more than tenfold ratio (90-\%-modulation) keeping a moderate insertion loss within an optical bandwidth of hundreds of GHz. Numerical simulations confirm the predictions by the derived analytical formulas of a high-contrast magneto-plasmonic modulation by the submicron ultra-small disk resonator.