Tunable terahertz optical antennas based on graphene ring structures

Liu, Penghong; Cai, Wei; Wang, Lei; Zhang, Xinzheng; Xu, Jingyi

doi:10.1063/1.3702819

Cited by 104 publications

(55 citation statements)

References 23 publications

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“…The dielectric layer D2 not only supports the graphene and metal strips, but also provides space for destructive interference as the case in metamaterial absorbers. 13 On the other hand, the top dielectric layer is for protecting the graphene and metal strips as well as providing extra degree of freedom for impedance matching so to shift the working frequency to lower band. To verify the effect of D1 on the absorbing screen's bandwidth, simulated results are displayed in Fig.…”

Section: Shift Of Frequency Bands and Influence Of Incident Anglesmentioning

confidence: 99%

“…10,11 The applications of graphene also cover wide frequency ranging from optical frequency to THz, [5][6][7][12][13][14][15][16][17] infrared to microwave band. [18][19][20] Among these works, tunable cloaks, 12 polarizers and metasurface are designed with help of electrically tunability of graphene sheet.…”

Section: Introductionmentioning

confidence: 99%

“…17,19,20 Graphene has also been studied in reconfigurable optical and THz antennas. [13][14][15] Even though graphene has been widely studied from lower THz to optical spectrums, its applications in microwave bands are much less cultivated. The reported works so far have focused on the characteristics of graphene transmission lines, [21][22][23] and applications are limited to some complementary components like antenna reflector.…”

Section: Introductionmentioning

confidence: 99%

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Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

Huang

Liu

2014

AIP Advances

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This paper proposes a new type of graphene based tunable radar absorbing screen. The absorbing screen consists of Hilbert curve metal strip array and chemical vapour deposition (CVD) graphene sheet. The graphene based screen is not only tunable when the chemical potential of the graphene changes, but also has broadband effective absorption. The absorption bandwidth is from 8.9GHz to 18.1GHz, ie., relative bandwidth of more than 68%, at chemical potential of 0eV, which is significantly wider than that if the graphene sheet had not been employed. As the chemical potential varies from 0 to 0.4eV, the central frequency of the screen can be tuned from 13.5GHz to 19.0GHz. In the proposed structure, Hilbert curve metal strip array was designed to provide multiple narrow band resonances, whereas the graphene sheet directly underneath the metal strip array provides tunability and averagely required surface resistance so to significantly extend the screen operation bandwidth by providing broadband impedance matching and absorption. In addition, the thickness of the screen has been optimized to achieve nearly the minimum thickness limitation for a nonmagnetic absorber. The working principle of this absorbing screen is studied in details, and performance under various incident angles is presented. This work extends applications of graphene into tunable microwave radar cross section (RCS) reduction applications.

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Section: Shift Of Frequency Bands and Influence Of Incident Anglesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

Huang

Liu

2014

AIP Advances

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“…Most importantly, these modes are sensitivie to electrostatic doping of graphene, making them highly attractive for electrical control of light on the nanometer scale. For these reasons, the interest in GPs is steadily increasing in theoretical and experimental communities [10,11].Different amazing physical phenomena involving GPs have already been studied, including waveguiding [9,[12][13][14], strong light-matter interaction [15][16][17] and enhanced light absorption [18][19][20]. Recent experimental studies of both propagating and cavity-like graphene plasmons have confirmed their extremely short wavelengths (i.e.…”

mentioning

confidence: 99%

Plasmons in graphene on uniaxial substrates

Arrazola

Hillenbrand

Nikitin

2014

Applied Physics Letters

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Placing graphene on uniaxial substrates may have interesting application potential for graphenebased photonic and optoelectronic devices. Here we analytically derive the dispersion relation for graphene plasmons on uniaxial substrates and discuss their momentum, propagation length and polarization as a function of frequency, propagation direction and both ordinary and extraordinary dielectric permittivities of the substrate. We find that the plasmons exhibit an anisotropic propagation, yielding radially asymmetric field patterns when a point emitter launches plasmons in the graphene layer.Graphene may open novel avenues for the development of ultra-compact nanoscale photonic and optoelectronic devices [1,2]. Particularly interesting applications are expected in optical information processing, where electromagnetic waves have to be guided and external control of their propagation is required. In future graphene-based photonic platforms this may be accomplished by manipulating graphene plasmons (GPs) [9], which are coherent electron oscillations in doped graphene coupled to an electromagnetic field. The electromagnetic modes exhibit a wavelength λ p much smaller than that of the free-space, λ p λ [3-9], which enables them to squeeze into extremely subwavelength volumes. Most importantly, these modes are sensitivie to electrostatic doping of graphene, making them highly attractive for electrical control of light on the nanometer scale. For these reasons, the interest in GPs is steadily increasing in theoretical and experimental communities [10,11].Different amazing physical phenomena involving GPs have already been studied, including waveguiding [9,[12][13][14], strong light-matter interaction [15][16][17] and enhanced light absorption [18][19][20]. Recent experimental studies of both propagating and cavity-like graphene plasmons have confirmed their extremely short wavelengths (i.e. high momenta), as well as their remarkable tunability by electrical gating [21][22][23][24][25].A deposition of graphene onto different metamaterial (anisotropic) substrates [26] could pave the way to promising hybrid optical elements and nanodevices includng biochemical sensors, polarizers and modulators [10]. However, the impact of an anisotropic material on intrinsic plasmons in graphene has not been addressed yet. In this letter we introduce a concept for manipulating the propagation of GPs with the use of anisotropic substrates. As a proof of concept, we consider the case of a uniaxial substrate. Uniaxial crys- * Electronic address: alexeynik@rambler.ru tals can be regarded as the long-wavelength limit of media composed by periodically-stacked layers (onedimensional photonic crystals) [32], as illustrated in Fig. 1. Uniaxial crystals as for example SiC or heteroepitaxial structures represent an important family of anisotropic media with a wide range of applications from photonics to electronics [27,31].In order to treat a periodic layered substrate as a uniaxial crystal, the lattice constant a has to be much smaller than the GP wa...

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“…In recent years, THz techniques have been used to study the electric states in graphene [25][26][27][28][29][30]. Given the ultra-high carrier mobility of graphene, it also has applications in THz optoelectronics such as transformation optics [23], tunable THz modulators [31][32][33][34][35], room-temperature THz detectors [36], THz optical antennas [37], etc. These graphene-based THz devices have important applications, such as in medical diagnostics, molecular biology, and homeland security.…”

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confidence: 99%

Gate-tunable nearly total absorption in graphene with resonant metal back reflector

Liu¹,

Liu²,

Wang³

et al. 2013

EPL

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The gate-tunable terahertz (THz) absorption of graphene layers with a resonant metal back reflector (RMBF) is theoretically investigated. We demonstrate that the THz absorption of graphene with RMBF can vary from nearly negligible to nearly total by tuning the external gate voltage. This peculiar nearly total THz absorption can be attributed to the Fabry-Perot cavity effect, which enhances the absorption and reduces the reflection of graphene. The absorption spectra of the graphene-RMBF structure can also be tailored in bandwidth and center frequency by changing the thickness and dielectric constant of the spacer layer. The optical properties of graphene is attracting increased attention because of the abundant potential applications within a wide spectral range from terahertz (THz) to visible frequencies . As an ultra-thin twodimensional (2D) carbon material, graphene is widely used in the transparent electrodes and optical display materials [1][2][3][4]. In recent years, THz techniques have been used to study the electric states in graphene [25][26][27][28][29][30]. Given the ultra-high carrier mobility of graphene, it also has applications in THz optoelectronics such as transformation optics [23], tunable THz modulators [31][32][33][34][35], room-temperature THz detectors [36], THz optical antennas [37], etc. These graphene-based THz devices have important applications, such as in medical diagnostics, molecular biology, and homeland security.To promote the applications of graphene within the THz frequency range, the interaction between graphene and THz waves should be enhanced. In the recent two years, various graphene plasmonics with different microstructures have been proposed to enhance the absorption of graphene [12][13][14][15][16][17][18][19][20][21]. In particular, nearly complete absorption can be achieved in periodically patterned graphene or microcavity [12,13]. The concept of perfect absorbers has initiated a new research area and has important applications in optoelectronics [12,[38][39][40]. However, fabricating periodically patterned graphene or placing it in an optical microcavity under current technological conditions remains difficult.Recently, Liu et al. proposed that the optical absorption of graphene layers on the top of a one-dimensional photonic crystal (1DPC) can be significantly enhanced within the visible spectral range because of photon localization [41]. In a similar manner, the absorption of * Electronic address: jtliu@semi.ac.cn † Electronic address: fhsu@issp.ac.cn graphene can also be increased within the THz spectra range [42]. The proposed 1DPC structures can be implemented using existing technologies. However, the photonic band gap (PBG) of 1DPC limits the spectrum bandwidth for the absorption enhancement of graphene. In fact, highly conducting metal films such as aluminum, silver, and gold can effectively reflect the electromagnetic wave within a wide spectral range from the middleinfrared region to the microwave region the same as a 1DPC [43]. Thus, the metal film can repla...

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Tunable terahertz optical antennas based on graphene ring structures

Cited by 104 publications

References 23 publications

Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

Graphene based tunable fractal Hilbert curve array broadband radar absorbing screen for radar cross section reduction

Plasmons in graphene on uniaxial substrates

Gate-tunable nearly total absorption in graphene with resonant metal back reflector

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