Absorption enhancement and total absorption in a graphene-waveguide hybrid structure

Guo, Jun; Wu, Leiming; Dai, Xiaoyu; Xiang, Yuanjiang; Fan, Dianyuan

doi:10.1063/1.4975706

Cited by 33 publications

(11 citation statements)

References 33 publications

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“…As a plasmonic material, graphene is also capable of supporting low-loss, highly confined and tunable (by chemical doping or electrostatic/magnetostatic gating) surface plasmon polaritons (SPPs) from terahertz (THz) to the mid-infrared (mid-IR) range [20][21][22]. Therefore, a great diversity of plasmonic metamaterials based on this material has also been devised for enhancing light absorption, such as graphene discs [23], ellipses [24], hole arrays [25,26], ribbons [27][28][29][30][31], rings [32], and graphene-based photonic crystals and hyperbolic metamaterials [33][34][35]. Alongside noble metals and graphene, polar dielectrics also offer an opportunity for simultaneous subdiffractional confinement through the stimulation of surface phonon polariton (SPhP) modes [36].…”

Section: Introductionmentioning

confidence: 99%

Tunable, omnidirectional, and nearly perfect resonant absorptions by a graphene-hBN-based hole array metamaterial

et al. 2018

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In this paper, we propose an electrically tunable mid-infrared plasmonic-phononic absorber with omnidirectional and polarization insensitive nearly perfect resonant absorption characteristics. The absorber consists of a graphene/hexagonal boron nitride (hBN)/graphene multilayer on top of a gold bottom reflector separated by a dielectric spacer. The graphene/hBN/graphene multilayer is patterned as a hole array in square lattice. We analytically and numerically prove that, due to the support of hybrid plasmon-phonon-polaritons, nearly perfect multi-resonant absorption peaks with high quality factors are obtained both inside and outside of the Reststrahlen band of hBN. As a result of the hybridization of graphene plasmons with the hyperbolic phonon polaritons of hBN, the high quality resonant absorptions of the metamaterial are almost unaffected by decreasing the phenomenological electron relaxation time of graphene. Moreover, the obtained resonances can be effectively tuned in practice due to the continuity of the graphene layers in the hole array metamaterial. These features make the graphene-hBN metamaterial a skeptical design for practical purposes and mid-infrared multi-functional operations such as sensing.

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Section: Introductionmentioning

confidence: 99%

Tunable, omnidirectional, and nearly perfect resonant absorptions by a graphene-hBN-based hole array metamaterial

et al. 2018

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“…To overcome this problem, various physical mechanisms [ 18 – 43 ] to enhance absorption of graphene in the visible region have been proposed, which include strong photon localization on the defect layer in one-dimensional (1D) photonic crystals [ 18 , 28 , 33 , 38 ], total internal reflection [ 19 , 20 , 23 , 27 ], surface plasmon resonances [ 21 , 22 , 30 , 31 , 33 ], evanescent diffraction orders of the arrays of metal nanoparticles [ 34 ], and critical coupling to guided mode resonances [ 25 , 26 , 32 , 34 , 35 , 37 , 39 – 41 ]. Besides the absorption enhancement in graphene, achieving multiband and broadband light absorption in graphene is also important for some graphene-based optoelectronic devices from a practical point of view.…”

Section: Introductionmentioning

confidence: 99%

Multiband and Broadband Absorption Enhancement of Monolayer Graphene at Optical Frequencies from Multiple Magnetic Dipole Resonances in Metamaterials

et al. 2018

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It is well known that a suspended monolayer graphene has a weak light absorption efficiency of about 2.3% at normal incidence, which is disadvantageous to some applications in optoelectronic devices. In this work, we will numerically study multiband and broadband absorption enhancement of monolayer graphene over the whole visible spectrum, due to multiple magnetic dipole resonances in metamaterials. The unit cell of the metamaterials is composed of a graphene monolayer sandwiched between four Ag nanodisks with different diameters and a SiO2 spacer on an Ag substrate. The near-field plasmon hybridizations between individual Ag nanodisks and the Ag substrate form four independent magnetic dipole modes, which result into multiband absorption enhancement of monolayer graphene at optical frequencies. When the resonance wavelengths of the magnetic dipole modes are tuned to approach one another by changing the diameters of the Ag nanodisks, a broadband absorption enhancement can be achieved. The position of the absorption band in monolayer graphene can be also controlled by varying the thickness of the SiO2 spacer or the distance between the Ag nanodisks. Our designed graphene light absorber may find some potential applications in optoelectronic devices, such as photodetectors.

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“…The interband absorption of the stacked graphene can be greatly enhanced by the effect of metal doping and the increase of the Fermi energy with bias voltage. In the proposed stacked structure, the resonance S 11 is totally caused by the graphene-metal sandwich, if the total absorption of the antenna is designed at frequency f = v2E F /(2πhc), S 11 can be greatly enhanced by increasing the E F through the electrostatic doping [55]. This tunability from the low absorption to unity absorption is quite important for the realization of infrared sensors.…”

Section: Tunability and Enhancement Of Optical Absorptionmentioning

confidence: 99%

“…This tunability from the low absorption to unity absorption is quite important for the realization of infrared sensors. Finally, the conductivity model of the doped graphene (electrostatically raising the graphene Fermi energy) to express the absorption enhancement by local-RPA model [55],…”

Section: Tunability and Enhancement Of Optical Absorptionmentioning

confidence: 99%

Dynamic Absorption Enhancement and Equivalent Resonant Circuit Modeling of Tunable Graphene-Metal Hybrid Antenna

Ullah

Nawi

Witjaksono³

et al. 2020

Sensors

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Plasmonic antennas are attractive optical components of the optoelectronic devices, operating in the far-infrared regime for sensing and imaging applications. However, low optical absorption hinders its potential applications, and their performance is limited due to fixed resonance frequency. In this article, a novel gate tunable graphene-metal hybrid plasmonic antenna with stacking configuration is proposed and investigated to achieve tunable performance over a broad range of frequencies with enhanced absorption characteristics. The hybrid graphene-metal antenna geometry is built up with a hexagon radiator that is supported by the Al2O3 insulator layer and graphene reflector. This stacked structure is deposited in the high resistive Si wafer substrate, and the hexagon radiator itself is a sandwich structure, which is composed of gold hexagon structure and two multilayer graphene stacks. The proposed antenna characteristics i.e., tunability of frequency, the efficiency corresponding to characteristics modes, and the tuning of absorption spectra, are evaluated by full-wave numerical simulations. Besides, the unity absorption peak that was realized through the proposed geometry is sensitive to the incident angle of TM-polarized incidence waves, which can flexibly shift the maxima of the absorption peak from 30 THz to 34 THz. Finally, an equivalent resonant circuit model for the investigated antenna based on the simulations results is designed to validate the antenna performance. Parametric analysis of the proposed antenna is carried out through altering the geometric parameters and graphene parameters in the Computer Simulation Technology (CST) studio. This clearly shows that the proposed antenna has a resonance frequency at 33 THz when the graphene sheet Fermi energy is increased to 0.3 eV by applying electrostatic gate voltage. The good agreement of the simulation and equivalent circuit model results makes the graphene-metal antenna suitable for the realization of far-infrared sensing and imaging device containing graphene antenna with enhanced performance.

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Absorption enhancement and total absorption in a graphene-waveguide hybrid structure

Cited by 33 publications

References 33 publications

Tunable, omnidirectional, and nearly perfect resonant absorptions by a graphene-hBN-based hole array metamaterial

Tunable, omnidirectional, and nearly perfect resonant absorptions by a graphene-hBN-based hole array metamaterial

Multiband and Broadband Absorption Enhancement of Monolayer Graphene at Optical Frequencies from Multiple Magnetic Dipole Resonances in Metamaterials

Dynamic Absorption Enhancement and Equivalent Resonant Circuit Modeling of Tunable Graphene-Metal Hybrid Antenna

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