# Plasmon Confinement by Carrier Density Modulation in Graphene

## TL;DR

This study demonstrates that carrier density modulation in graphene can confine plasmon resonances, with terahertz spectroscopy revealing localized plasmon modes in periodically patterned micro-ribbons.

## Contribution

It introduces a method to confine plasmons in graphene through periodic carrier density modulation, advancing plasmonic control in 2D materials.

## Key findings

- Two distinct plasmon modes localized in different ribbon arrays.
- Plasmons are selectively excited depending on the Fermi energy.
- Carrier density modulation enables plasmon confinement in graphene.

## Abstract

We investigate plasmon resonances in graphene with periodic carrier density modulation. The period is 8 um, and each period consists of 1.7- and 6.3-um-wide ribbons with different density. Using terahertz spectroscopy, we show two plasmon modes with their electric field mostly localized in the 1.7- or 6.3-um-wide ribbon arrays. We also show that plasmons are excited only in one of the micro-ribbon arrays when the Fermi energy of the other micro-ribbon array is set close to the charge neutrality point. These results indicate that plasmons can be confined by the carrier density modulation.

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Source: https://tomesphere.com/paper/1812.01266