Dynamical tuning between nearly perfect reflection, absorption, and transmission of light via graphene/dielectric structures

TL;DR

This paper demonstrates a method to dynamically tune a graphene/dielectric structure to achieve nearly perfect reflection, absorption, or transmission of light by adjusting the graphene's Fermi level, with additional control via cylindrical defects.

Contribution

It introduces a graphene/dielectric structure capable of switching between reflection, absorption, and transmission regimes by Fermi level tuning, including defect-based scattering control.

Findings

All three regimes achieved in the THz regime and below

Fermi level tuning enables dynamic control of optical properties

Cylindrical defects provide additional scattering control

Abstract

Exerting well-defined control over the reflection $(R)$, absorption $(A)$, and transmission $(T)$ of electromagnetic waves is a key objective in quantum optics. To this end, one often utilizes hybrid structures comprised of elements with different optical properties in order to achieve features such as high $R$ or high $A$ for incident light. A desirable goal would be the possibility to tune between all three regimes of nearly perfect reflection, absorption, and transmission within the same device, thus swapping between the cases $R\to 1$, $A\to1$, and $T\to1$ dynamically. We here show that a dielectric interfaced with a graphene layer on each side allows for precisely this: by tuning only the Fermi level of graphene, all three regimes can be reached in the THz regime and below. Moreover, we show that the inclusion of cylindrical defects in the system offers a different type of control of the scattering of electromagnetic waves by means of the graphene layers.