Tunable light trapping and absorption enhancement with graphene ring arrays

TL;DR

This paper proposes periodic graphene ring arrays that utilize tunable surface plasmon resonance to enhance light trapping and absorption, enabling multi-band photodetection with high efficiency and spectral tunability.

Contribution

Introduction of a novel graphene ring array design for tunable light trapping and multi-band absorption enhancement in the mid-infrared and THz regimes.

Findings

Enhanced absorption in nearby materials by over an order of magnitude.

Achieved multi-band plasmonic absorption with concentric graphene rings.

Demonstrated potential for high-efficiency, tunable multi-color photodetectors.

Abstract

Surface plasmon resonance (SPR) has been intensively studied and widely employed for light trapping and absorption enhancement. In the mid-infrared and terahertz (THz) regime, graphene supports the tunable SPR via manipulating its Fermi energy and enhances light-matter interaction at the selective wavelength. In this work, periodic arrays of graphene rings are proposed to introduce tunable light trapping with good angle polarization tolerance and enhance the absorption in the light-absorbing materials nearby to more than one order. Moreover, the design principle here could be set as a template to achieve multi-band plasmonic absorption enhancement by introducing more graphene concentric rings into each unit cell. This work not only opens up new ways of employing graphene SPR, but also leads to practical applications in high-performance simultaneous multi-color photodetection with high efficiency and tunable spectral selectivity.