Fields radiated by a nanoemitter in a graphene sheet

TL;DR

This paper investigates the electromagnetic fields radiated by a nanoemitter on a graphene sheet, revealing frequency-dependent behaviors, a high-intensity core region dominated by surface plasmons, and controllable interaction properties for optoelectronic applications.

Contribution

It provides a detailed analysis of the electromagnetic field distribution around a nanoemitter on graphene, highlighting the role of surface plasmons and external gating in controlling the field characteristics.

Findings

Field exhibits strong dependence on frequency, distance, and dipole orientation.

A high-intensity core region dominated by surface plasmons can be externally controlled.

Large coupling between nanoemitters and surface plasmons suggests potential for quantum-optics applications.

Abstract

The extraordinary properties of graphene make it a very promising material for use in optoelectronics. However, this is still a nascent field, where some basic properties of the electromagnetic field in graphene must be explored. Here we report on the fields radiated by a nanoemitter lying on a graphene sheet. Our results show that this field presents a rich dependence on both frequency, distance to the source and dipole orientation. This behavior is attributed to distinct peculiarities on the density of electromagnetic states in the graphene sheet and the interaction between them. The field is mainly composed of an core region of high-intensity electromagnetic field, dominated by surface plasmons, and an outer region where the field is practically the same it would be for an emitter in vacuum. Within the core region, the intensity of the electric field is several orders of magnitude larger than what it would be in vacuum. Importantly, the size of this core region can be controlled thorough external gates, which opens up many interesting applications in, for instance, surface optics and spectroscopy. Additionally, the large coupling between nanoemitters and surface plasmons makes graphene sheets a propitious stage for quantum-optics, in which the interaction between quantum objects could be externally tailored at will.