Polarization-independent and angle-insensitive broadband absorber with a target-patterned graphene layer in the terahertz regime

Huang, Xin; He, Wei; Yang, Fan; Jia, Renxu; Gao, Bing; Zhang, Weili

doi:10.1364/oe.26.025558

Cited by 117 publications

(42 citation statements)

References 34 publications

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“…Graphene, as one kind of tunable photoelectric material, is often applied to regulate the absorption amplitude and frequency range of a MMA. The surface conductivity of a graphene sheet relates primarily to its Fermi energy, which can be easily controlled by applying bias voltage or electrostatic chemical doping [33][34][35]. Here, the Fermi level (E f ) of the CGS graphene sheet placed on the top layer of the MMA structure is adjusted dynamically by changing the external bias voltage V g , as shown in Figure 1b.…”

Section: Resultsmentioning

confidence: 99%

“…However, most of these MMAs are usually narrowband, which greatly limits their applications in some circumstances. Numerous efforts have been made to realize multi-and broadband absorption by various methods, including multilayer graphene structures [32], multiple graphene resonators in a unit cell [33], structured graphene with gradually changing geometric sizes [34], and other hybrid-patterned metal-graphene composite structures [33][34][35][36][37]. Although the broad absorption bandwidth of the MMAs can be enhanced, most of them still suffer from some drawbacks, including difficulty with absorption tuning via biasing, significant polarization and incident angle dependence, and complicated fabrication technology.…”

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confidence: 99%

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A Broadband Tunable Terahertz Metamaterial Absorber Based on Single-Layer Complementary Gammadion-Shaped Graphene

2020

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We present a simple design of a broadband tunable metamaterial absorber (MMA) in the terahertz (THz) region, which consists of a single layer complementary gammadion-shaped (CGS) graphene sheet and a polydimethylsiloxane (PDMS) dielectric substrate placed on a continuous metal film. The Fermi energy level (E f ) of the graphene can be modulated dynamically by the applied DC bias voltage, which enables us to electrically control the absorption performance of the proposed MMA flexibly. When E f = 0.8 eV, the relative bandwidth of the proposed MMA, which represents the frequency region of absorption beyond 90%, can reaches its maximal value of 72.1%. Simulated electric field distributions reveal that the broadband absorption mainly originates from the excitation of surface plasmon polaritons (SPPs) on the CGS graphene sheet. Furthermore, the proposed MMA is polarization-insensitive and has wide angles for both transverse-electric (TE) and transverse-magnetic (TM) waves in the broadband frequency range. The broadband absorption capacity of the designed MMA can be effectively adjusted by varying the Fermi energy level of graphene. Lastly, the absorbance of the MMA can be adjusted from 42% to 99.1% by changing the E f from 0 eV to 0.8 eV, which is in agreement with the theoretical calculation by using the interference 41theory. Due to its simple structure and flexible tunability, the proposed MMA has potential application prospects in tunable filtering, modulators, sensing, and other multispectral devices.Materials 2020, 13, 860 2 of 11 candidate material because of its unique properties, including optical transparency, electron mobility, and excellent mechanical properties [15][16][17][18]. The most attractive property is that the permittivity and conductivity of graphene can be dynamically tuned by changing the Fermi energy through chemical doping or external bias voltage, achieving dynamically tunable MMAs [19][20][21].In the last few years, MMAs based on graphene have received increasing interest and have achieved tremendous progress. Various MMAs based on patterned graphene structures, such as disks [21], ribbons [22,23], patches [24], cross fishnets [25], and other microstructures [26][27][28][29][30][31], have been proposed to enhance the absorption. It is believed that the perfect absorption of the graphene-based MMA is mainly originated from excitation of surface plasmon resonances (SPRs) in the periodic patterned graphene structures. However, most of these MMAs are usually narrowband, which greatly limits their applications in some circumstances. Numerous efforts have been made to realize multi-and broadband absorption by various methods, including multilayer graphene structures [32], multiple graphene resonators in a unit cell [33], structured graphene with gradually changing geometric sizes [34], and other hybrid-patterned metal-graphene composite structures [33][34][35][36][37]. Although the broad absorption bandwidth of the MMAs can be enhanced, most of them still suffer from some drawbacks, including dif...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

A Broadband Tunable Terahertz Metamaterial Absorber Based on Single-Layer Complementary Gammadion-Shaped Graphene

2020

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“…Figure 2 gives the detailed structure of the broadband absorption-controllable absorber, which consists of a nanostructure graphene layer, a SiO 2 -doped Si-SiO 2 sandwich structure, a gold ground. The nested square ring and patch of graphene can form resonance and excite localized surface plasmon resonances, which are hybridized with each other leading to a broadband absorption band [24]. The diagonals connect discrete units so that the electrostatic doping of periodic graphene array becomes much easier.…”

Section: Methodsmentioning

confidence: 99%

“…The multiple bands can be realized either by integrating several resonators within a unit cell or stacking multiple layers of the resonators with different size separated by dielectric layers [18,19,20]. The broad bandwidth is implemented by adopting gradient structural elements, combining multilayer resonators, or nesting concentric resonators [21,22,23,24,25]. All of the mentioned absorbers can only regulate a single parameter in a specific design.…”

Section: Introductionmentioning

confidence: 99%

Graphene-Based THz Absorber with a Broad Band for Tuning the Absorption Rate and a Narrow Band for Tuning the Absorbing Frequency

Zhou

Liu

et al. 2019

Nanomaterials

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In this paper, we propose a broadband absorption-controllable absorber based on nested nanostructure graphene and a narrowband frequency-tunable absorber utilizing gold-graphene hybrid structure in the terahertz regime. The numerical simulation results showed that the absorption of the broadband absorber can be changed from 27% to more than 90% over 0.75 to 1.7 THz by regulating the chemical potential of graphene. With the same regulation mechanism, the absorbing peak of the narrowband absorber can be moved from 2.29 to 2.48 THz continuously with absorption of 90%. Furthermore, via the cascade of the two types of absorbers, an independently tunable dual-band absorber is constituted. Its absorption spectrum is the superposition of absorption-controllable absorber and frequency-tunable absorber. The absorptivity and operating frequency of the two absorbing bands can be tuned independently without mutual inference. Moreover, it is insensitive to the polarization and it maintains high absorption over a wide range of incident angle. For the flexibility, tunability as well as the independence of polarization and angle, this design has wide prospects in various applications.

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“…MM absorbers have widely been investigated with a variety of artificial metatoms and characteristic of block transmission and have also been recognized to have many potential applications. [12][13][14][15] However, the development and practical application of MM absorbers are greatly limited due to their less lattice constant 16 and complex technological process and being easily interfered with environmental factors. 17 Most recently, planar nanostructures that can provide high-efficiency functionality in much smaller volumes have been focused on intensive investigations.…”

Section: Introductionmentioning

confidence: 99%

High-efficiency and ultrabroadband flexible absorbers based on transversely symmetrical multi-layer structures

Wang

et al. 2019

AIP Advances

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Two ultrabroadband and omnidirectional perfect absorbers based on transversely symmetrical multilayer structures are presented, which are achieved by four absorptive metal chromium (Cr) layers, antireflection coatings, and the substrates, glass and PMMA, in the middle. At the initial step, the proposed planar structure shows an average absorption of ∼93% over the visible (VIS) and near-infrared range from 400 to 2500 nm and 98% in the VIS range. The optimum flat is optically characterized by the transfer matrix method and local metal-insulator-metal resonance under illumination with transverse-electric and transverse-magnetic polarization waves. The multilayer materials, which are deposited on an intermediate substrate by e-beam evaporation, outperform the previously reported absorbers in the fabrication process and exhibit a great angular tolerance of up to 60°. Afterward, we present a novel symmetrical flexible absorber with the PMMA substrate, which shows not only perfect absorption but also the effect of stress equilibrium. The presented devices are expected to pave the way for practical use of solar-thermal energy harvesting.

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Polarization-independent and angle-insensitive broadband absorber with a target-patterned graphene layer in the terahertz regime

Cited by 117 publications

References 34 publications

A Broadband Tunable Terahertz Metamaterial Absorber Based on Single-Layer Complementary Gammadion-Shaped Graphene

A Broadband Tunable Terahertz Metamaterial Absorber Based on Single-Layer Complementary Gammadion-Shaped Graphene

Graphene-Based THz Absorber with a Broad Band for Tuning the Absorption Rate and a Narrow Band for Tuning the Absorbing Frequency

High-efficiency and ultrabroadband flexible absorbers based on transversely symmetrical multi-layer structures

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