Photonic topological insulators
Alexander B. Khanikaev,S. Hossein Mousavi,Wang-Kong Tse,Mehdi Kargarian,Allan H. MacDonald,Gennady Shvets +5 more
TLDR
It is shown that metacrystals-superlattices of metamaterials with judiciously designed properties-provide a platform for designing topologically non-trivial photonic states, similar to those identified for condensed-matter topological insulators.Abstract:
Recent progress in understanding the topological properties of condensed matter has led to the discovery of time-reversal-invariant topological insulators. A remarkable and useful property of these materials is that they support unidirectional spin-polarized propagation at their surfaces. Unfortunately topological insulators are rare among solid-state materials. Using suitably designed electromagnetic media (metamaterials) we theoretically demonstrate a photonic analogue of a topological insulator. We show that metacrystals-superlattices of metamaterials with judiciously designed properties-provide a platform for designing topologically non-trivial photonic states, similar to those that have been identified for condensed-matter topological insulators. The interfaces of the metacrystals support helical edge states that exhibit spin-polarized one-way propagation of photons, robust against disorder. Our results demonstrate the possibility of attaining one-way photon transport without application of external magnetic fields or breaking of time-reversal symmetry. Such spin-polarized one-way transport enables exotic spin-cloaked photon sources that do not obscure each other.read more
Citations
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Valley-controlled propagation of pseudospin states in bulk metacrystal waveguides
TL;DR: In this article, the controllable propagation of pseudospin states in three-dimensional bulk metacrystal waveguides by valley degree of freedom was realized by converting the Dirac cones in time-reversal-invariant photonic crystals.
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Double Dirac cone in two-dimensional phononic crystals beyond circular cells
TL;DR: In this paper, the formation of a double Dirac cone in two-dimensional phononic crystals consisting of either hexagonal or triangular columns in air was investigated. And the authors showed that a topological phase transformation induced by energy band inversion with dipolar and quadrupolar states occurs near the double dirac cone, and the results suggest a new route for designing topological and zero-refractive-index acoustic devices.
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Conical intersections for light and matter waves
TL;DR: In this paper, the design, theory, and applications of two-dimensional periodic lattices hosting conical intersections in their energy-momentum spectrum are reviewed, and the best known example is the Dirac cone, where propagation is governed by an effective Dirac equation, with electron spin replaced by a 'fermionic' half-integer pseudospin.
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Anomalous Light Scattering by Topological PT -symmetric Particle Arrays
TL;DR: In this paper, a conjugate pair of complex topological edge modes in a non-Hermitian -symmetric system can give rise to an anomalous sideway scattering when they are simultaneously excited by a plane wave.
Journal Article
Topological Triplon Modes and Bound States in a Shastry-Sutherland Magnet
Paul McClarty,Frank Kruger,Tatiana Guidi,Stewart F. Parker,Keith Refson,Tony Parker,Dharmalingam Prabhakaran,Radu Coldea +7 more
TL;DR: A detailed experimental investigation on the spin excitations in SrCu2(BO3)2 under an external magnetic confirms the existence of topological triplon modes in this experimental realization of the Shastry-Sutherland model as mentioned in this paper.
References
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Colloquium: Topological insulators
M. Z. Hasan,Charles L. Kane +1 more
TL;DR: In this paper, the theoretical foundation for topological insulators and superconductors is reviewed and recent experiments are described in which the signatures of topologically insulators have been observed.
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Topological insulators and superconductors
Xiao-Liang Qi,Shou-Cheng Zhang +1 more
TL;DR: Topological superconductors are new states of quantum matter which cannot be adiabatically connected to conventional insulators and semiconductors and are characterized by a full insulating gap in the bulk and gapless edge or surface states which are protected by time reversal symmetry.
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Negative Refraction Makes a Perfect Lens
TL;DR: The authors' simulations show that a version of the lens operating at the frequency of visible light can be realized in the form of a thin slab of silver, which resolves objects only a few nanometers across.
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The Electrodynamics of Substances with Simultaneously Negative Values of ∊ and μ
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Experimental Verification of a Negative Index of Refraction
TL;DR: These experiments directly confirm the predictions of Maxwell's equations that n is given by the negative square root ofɛ·μ for the frequencies where both the permittivity and the permeability are negative.