Negative refraction in graphene-based hyperbolic metamaterials

Sreekanth, Kandammathe Valiyaveedu; Luca, Antonio De; Strangi, Giuseppe

doi:10.1063/1.4813477

Cited by 138 publications

(92 citation statements)

References 32 publications

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“…Negative refraction has been demonstrated from double negative metamaterial [1] to metaldielectric multilayers [2][3], nanowire metamaterials [4][5], polar dielectrics [6], photonic crystals [7],antiferromagnets [8], hyper crystals [9,10] and so on. Metal dielectric multilayers have been intensively used in constructing so called indefinite or hyperbolic metamaterials [2,3,11,12] where the principal components of the dielectric tensor have opposite sign.…”

mentioning

confidence: 99%

“…Metal dielectric multilayers have been intensively used in constructing so called indefinite or hyperbolic metamaterials [2,3,11,12] where the principal components of the dielectric tensor have opposite sign. Hyperbolic metamaterials possess the ability of negative refraction due to its hyperbolic iso-frequency [2][3][4][5][6]13]. But as they are made from metals, loss in individual metal layer greatly reduces its performance and practical applications.…”

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confidence: 99%

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Broad angle negative refraction in lossless all dielectric or semiconductor based asymmetric anisotropic metamaterial

Sayem

Mahdy

Rahman

2015

J. Opt.

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In this article, it has been theoretically shown that broad angle negative refraction is possible with asymmetric anisotropic metamaterials constructed by only dielectrics or lossless semiconductors at the telecommunication and relative wavelength range. Though natural uniaxial materials can exhibit negative refraction, the maximum angle of negative refraction and critical incident angle lie in a very narrow range. This notable problem can be overcome by our proposed structure. In our structures, negative refraction originates from the highly asymmetric elliptical iso-frequency.This is artificially created by the rotated multilayer sub-wavelength dielectric/semiconductor stack, which act as an effective asymmetric anisotropic metamaterial.This negative refraction is achieved without using any negative permittivity materials such as metals. As we are using simple dielectrics, fabrication of such structures would be less complex than that of the metal based metamaterials. Our proposed ideas have been validated numerically and also by the full wave simulations considering both the effective medium approach and realistic structure model. This device might find some important applications in photonics and optoelectronics.

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confidence: 99%

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confidence: 99%

Broad angle negative refraction in lossless all dielectric or semiconductor based asymmetric anisotropic metamaterial

Sayem

Mahdy

Rahman

2015

J. Opt.

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“…These materials can mimic some of the properties of negative-index materials such as negative refraction [1][2][3][4]. It is also possible to tailor such materials by going from elliptic to hyperbolic dispersion relations [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Enhancement of electromagnetically induced transparency in metamaterials using long range coupling mediated by a hyperbolic material

Guo¹,

Jiang²,

Li³

et al. 2018

Opt. Express

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Near-field coupling is a fundamental physical effect, which plays an important role in the establishment of classical analog of electromagnetically induced transparency (EIT). However, in a normal environment the coupling length between the bright and dark artificial atoms is very short and far less than one wavelength, owing to the exponentially decaying property of near fields. In this work, we report the realization of a long range EIT, by using a hyperbolic metamaterial (HMM) which can convert the near fields into high-k propagating waves to overcome the problem of weak coupling at long distance. Both simulation and experiment show that the coupling length can be enhanced by nearly two orders of magnitude with the aid of a HMM. This long range EIT might be very useful in a variety of applications including sensors, detectors, switch, long-range energy transfer, etc.

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“…In the case for transmission of an electron through a higher barrier than its incoming energy, the electron turns into a hole within the barrier region, with its momentum directed in the reversed direction, resulting in a negative refractive index [11][12][13][14][15][16][17][18][19] causing the electron beam to focus at a point, thereby producing a Veselago lens. There is always some probability for the electron to tunnel onto the other side of the barrier, which we have calculated in this paper.…”

Section: Introductionmentioning

confidence: 99%

Effect of energy band gap in graphene on negative refraction through the veselago lens and electron conductance

Dahal

Gumbs

2017

Journal of Physics and Chemistry of Solids

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A remarkable property of intrinsic graphene is that upon doping, electrons and holes travel through the monolayer thick material with constant velocity which does not depend on energy up to about 0.3 eV (Dirac fermions), as though the electrons and holes are massless particles and antiparticles which move at the Fermi velocity vF . Consequently, there is Klein tunneling at a p − n junction, in which there is no backscattering at normal incidence of massless Dirac fermions. However, this process yielding perfect transmission at normal incidence is expected to be affected when the group velocity of the charge carriers is energy dependent and there is non-zero effective mass for the target particle. We investigate how away from normal incidence the combined effect of incident electron energy and band gap parameter ∆ can determine whether a p − n junction would allow focusing of an electron beam by behaving like a Veselago lens with negative refractive index. We demonstrate that there is a specific region in − ∆ space where the index of refraction is negative, i.e., where monolayer graphene behaves as a metamaterial. Outside this region, the refractive index may be positive or there may be no refraction at all. We compute the ballistic conductance across a p − n junction as a function of ∆ and and compare our results with those for a single electrostatic potential barrier and multiple barriers.

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Negative refraction in graphene-based hyperbolic metamaterials

Cited by 138 publications

References 32 publications

Broad angle negative refraction in lossless all dielectric or semiconductor based asymmetric anisotropic metamaterial

Broad angle negative refraction in lossless all dielectric or semiconductor based asymmetric anisotropic metamaterial

Enhancement of electromagnetically induced transparency in metamaterials using long range coupling mediated by a hyperbolic material

Effect of energy band gap in graphene on negative refraction through the veselago lens and electron conductance

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