Omnidirectional absorption in nanostructured metal surfaces

Abstract

General conditions for total light absorptionWe find it appropriate to use a Hamiltonian formalism to recast Maxwell's equations in the form

Plasmonics in atomically thin materials

“…Complete optical absorption has been studied and observed over many frequency ranges in disordered metal films [72,73], through lattice resonances in gratings and planar metamaterials [74][75][76][77][78][79][80], assisted by localized plasmonic resonances [81,82], using multilayer structures [83], and in overdense plasma [84]. However, the possibility of achieving complete optical absorption in atomically thin films offers additional advantages, as we discuss below.…”

Complete Optical Absorption in Periodically Patterned Graphene

“…In this context, the Salisbury screen [6,7], consisting of a thin absorbing layer placed above a reflecting surface, has been known to produce TLA, and it can be integrated in thin structures using magnetic-mirror metamaterials [8]. Similar phenomena have been reported at infrared (IR) [9][10][11] and microwave [12,13] frequencies, including omnidirectional TLA [14], which has been realized by using periodic surfaces supporting localized plasmon excitations.The availability of high-quality graphene as a stable material with extraordinary (opto)electronic properties [15-17] makes a compelling case for exploring its ability to harvest light for potential application to optoelectronics, with the advantage of being optically tunable via electrostatic doping [18]. However, a single sheet of homogeneous graphene is poorly absorbing [19] (about 2.3% absorption), so the challenge is to transform it into a perfect absorber, for which we can rely on its power to host extremely confined plasmons [20,21].…”

Broadband polarization-independent resonant light absorption using ultrathin plasmonic super absorbers

“…By structuring noble metal surfaces on the subwavelength scale, localized and delocalized surface plasmon resonances can be designed to produce high absorption on otherwise refl ective surfaces. Resonant light absorption in metallic structures has been widely studied both theoretically and experimentally in arrays of metallic gratings 1 -5 , nanoparticles 6,7 and subwavelength slits 8,9 . Metamaterials are also promising candidates to enhance electromagnetic wave absorption, and have been shown to yield perfect absorption at microwave 10 , terahertz 11 and infrared 12 -14 frequencies.…”

“…Metamaterials are also promising candidates to enhance electromagnetic wave absorption, and have been shown to yield perfect absorption at microwave 10 , terahertz 11 and infrared 12 -14 frequencies. To date, however, resonant absorption schemes using plasmonic nanostructures and metamaterials have been designed to absorb light within a narrow wavelength range, and with few exceptions 6,7,14 , the resonant absorption behaviour strongly depends on the incident polarization. Achieving a resonant response that spans a broad wavelength range is required for broadband thin-fi lm thermal emitters 15 , and thermophotovoltaic 12 cells, as well as plasmonic scatterers 16 -18 for photovoltaic cells.…”