Tunable mid-infrared coherent perfect absorption in a graphene meta-surface

Abstract

Graphene has drawn considerable attention due to its intriguing properties in photonics and optoelectronics. However, its interaction with light is normally rather weak. Meta-surfaces, artificial structures with single planar function-layers, have demonstrated exotic performances in boosting light-matter interactions, e.g., for absorption enhancement. Graphene based high efficiency absorber is desirable for its potential applications in optical detections and signal modulations. Here we exploit graphene nanoribbons based meta-surface to realize coherent perfect absorption (CPA) in the mid-infrared regime. It was shown that quasi-CPA frequencies, at which CPA can be demonstrated with proper phase modulations, exist for the grapheme meta-surface with strong resonant behaviors. The CPA can be tuned substantially by merging the geometric design of the meta-surface and the electrical tunability of graphene. Furthermore, we found that the graphene nanoribbon meta-surface based CPA is realizable with experimentally achievable graphene sample.

Coherent perfect absorbers: linear control of light with light

“…Another viable method to realize CPAs, particularly at terahertz frequencies, is to use graphene as the absorbing medium [48,50,[74][75][76][77]. Coherent control of absorption has been experimentally demonstrated for a 30-layer graphene film sandwiched between silica substrates, with strong modulation (80%) observed in the absorption [75].…”

“…Electrostatic doping is appealing because it is easily tunable [50,76], but requires a substrate. For free-standing single-layer graphene CPAs [74], chemical doping is required.…”

“…There are various methods to reach the required 50% single-beam absorption, such as increasing the carrier concentration through chemical doping [74,79], applying an electrostatic potential to change the Fermi level [50,[79][80][81][82], patterning the graphene sheet to induce local resonances [76,83] or using multilayer graphene [48,75].…”

Impact of Graphene on the Polarizability of a Neighbour Nanoparticle: A Dyadic Green’s Function Study

“…One possible method for overcoming such a difficulty is by computing the effective conductivity of the metamaterial, in this case the plasmonic graphene grating. The general method for accomplishing this was given in [60] and was later applied to the problem of tuning total absorption in graphene [61], but no details of its calculation were given. Instrumental to the calculation of the effective conductivity is the knowledge of the reflection and transmission Fresnel coefficients.…”

Midinfrared Surface Plasmons in Carbon Nanotube Plasmonic Metasurface

“…Plasmonic structures are used in sensing [1,2], nonlinear optics [3,4], and nanophotonics [5]. Since SP modes are characterized by the large enhancement of the electromagnetic field, plasmonic metasurfaces are being investigated to improve light harvesting efficiency in solar cells [6][7][8] and to overcome low intrinsic absorption of monolayer graphene [9][10][11][12][13]. In plasmonic structures, the field is primarily localized in the dielectric adjacent to metal, which results in an additional absorption in the vicinity of SP resonance [14,15].…”