Enhanced universal absorption of graphene in a Salisbury screen

Ying, Xiangxiao; Pu, Yang; Luo, Yong; Peng, Hao; Li, Zhe; Jiang, Yadong; Xu, Jimmy; Liu, Zhijun

doi:10.1063/1.4973898

Cited by 15 publications

(8 citation statements)

References 42 publications

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“…The most effective frequency tuning is achieved with the mobility between µ m = 1000 cm 2 V −1 s −1 and µ m = 2000 cm 2 V −1 s −1 . This mobility range is also quite reasonable and can be obtained using CVD-grown graphene [21]- [23], [45].…”

Section: A Frequency-tunable Absorbersupporting

confidence: 65%

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Toward Ultimate Control of Terahertz Wave Absorption in Graphene

Wang

Tretyakov

2019

IEEE Trans. Antennas Propagat.

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It is commonly believed that weak light-matter interactions in low-mobility graphene dramatically limits tunability of graphene-based optoelectronic devices, such as tunable absorbers or switches. In this paper, we use a simple circuit model to understand absorption in graphene sheets. In particular, we show that light interacts weakly also with very high-mobility graphene sheets and propose systematic design means to overcome these problems. The results have allowed us to demonstrate in the terahertz band that perfect absorption with excellent electrical tunability can be achieved within a wide span of mobility values (from 200 to 20000 cm 2 V −1 s −1 ) which almost covers the whole range of ever reported room-temperature mobilities. Remarkably, concentrating on the most practical low-mobility graphene devices, we exemplify our theory with two cases: frequencytunable and switchable absorbers with near 100% modulation efficiencies. Our work provides systematic and instructive insights into the design of highly tunable absorbers, without restrictions on graphene mobility. The design strategy and the developed analytical model can, in principle, be generalized to other wavelength regions from microwave to mid-infrared range, and other twodimensional materials such as transition metal dichalcogenides (TMDs) and black phosphorus.

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Section: A Frequency-tunable Absorbersupporting

confidence: 65%

“…In this case, perfect absorption may be possible even without the assistance of metallic patches. This explains the enhanced absorption of graphene Salisbury screen at TE grazing incidences reported in [44], [45].…”

Section: A Analytical Modelingmentioning

confidence: 73%

Toward Ultimate Control of Terahertz Wave Absorption in Graphene

Wang

Tretyakov

2019

IEEE Trans. Antennas Propagat.

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“…But, it is still a challenge, as pointed out in the very recent reports [ 44 – 46 ]. At present, different approaches have been proposed to broaden the bandwidth of graphene absorption in wide frequency range from THz [ 44 – 62 ] and infrared [ 63 – 65 ] to optical frequencies [ 19 , 23 , 29 , 31 , 34 – 36 , 38 – 40 , 43 ]. Especially, a multi-resonator approach was proven to be a very effective method to resolve the bandwidth limitation of graphene absorption in the THz and infrared regions [ 45 , 46 , 62 , 63 ].…”

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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“…Due to this sandwich structure, there exist two resonant cavities which are composed by the graphene and multi‐layer dielectrics, when the THz signal is being absorbed fully which results ‘0’ code (the THz wave reflection is 0.0425). When the gate voltage is unbiased, the graphene just works as a thin film (means above 2.3% of absorption from the previous study [20]), then a larger amplitude of signal can be detected and this could be translated into the digital signal ‘1’ code (the THz wave reflection reaches 0.9492) [21, 22]. The device can be characterised using a THz imaging and spectroscopy setup based on a Virginia Diode, Inc. multiplier source, capable of providing CW radiation in the 620–700 GHz frequency band and a broadband Schottky diode detector (as shown in Fig.…”

Section: Designmentioning

confidence: 99%

High‐modulation depth modulator based on double‐layer graphene with a low bias voltage

Zhou

Xiao

et al. 2019

Micro & Nano Letters

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An efficient modulation can be obtained by graphene due to its outstanding light-matter interaction, and many kinds of modulators based on graphene have been studied during the last couple of years. However, there still exist unsolved issues in graphene-based modulators, such as how to make a balance between modulation depth and modulation bandwidth. This work proposes a reflective modulator with relatively highmodulation depth and wide working bandwidth. The proposed modulator has a simple five-layered structure of graphene-silica-graphenesilicon-metal. They use an effective method of finite element method to simulate the performance of this modulator, and obtain a modulation depth of 96% with a low bias voltage of ∼4 V. Furthermore, they calculate the modulation speed by the equivalent circuit method, and obtain the maximum modulation speed of about 25 kHz and a wide broadband of 72 kHz from theoretical analysis. Therefore, this high-performance modulator provides an effective method for terahertz communication devices.

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Enhanced universal absorption of graphene in a Salisbury screen

Cited by 15 publications

References 42 publications

Toward Ultimate Control of Terahertz Wave Absorption in Graphene

Toward Ultimate Control of Terahertz Wave Absorption in Graphene

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

High‐modulation depth modulator based on double‐layer graphene with a low bias voltage

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