Tunable THz Switch-Filter Based on Magneto-Plasmonic Graphene Nanodisk

TL;DR

This paper introduces a tunable terahertz switch and filter device based on magneto-plasmonic graphene nanodisks, demonstrating controllable transmission and filtering capabilities through magnetic and chemical potential tuning.

Contribution

It presents a novel graphene-based THz device that functions as a tunable switch and filter, utilizing magnetic and chemical potential control for improved performance.

Findings

Achieves transmission at 5.33 THz with 12.7% bandwidth using a 0.61T magnetic field.

Demonstrates an ON/OFF ratio better than 20 dB by switching magnetic field or chemical potential.

Provides a Q-factor of 7.8 with low insertion loss of -2 dB.

Abstract

We propose and analyze a multifunctional THz device which can operate as a tunable switch and a filter. The device consists of a circular graphene nanodisk coupled to two nanoribbons oriented at $90^\circ$ to each other. The graphene elements are placed on a dielectric substrate. The nanodisk is magnetized by a DC magnetic field normal to its plane. The physical principle of the device is based on the propagation of surface plasmon-polariton waves in the graphene nanoribbons and excitation of dipole modes in the nanodisk. Numerical simulations show that 0.61T DC magnetic field provides transmission (regime ON) at the frequency 5.33 THz with the bandwidth 12.7$\%$ and filtering with the Q-factor equals to 7.8. At the central frequency, the insertion loss is around -2 dB and the reflection coefficient is -43 dB. The regime OFF can be achieved by means of switching DC magnetic field to zero value or by switching chemical potential of the nanodisk to zero with the ON/OFF ratio better than 20 dB. A small central frequency tuning by chemical potential is possible with a fixed DC magnetic field.