Photonic Floquet topological insulators
Mikael C. Rechtsman,Julia M. Zeuner,Yonatan Plotnik,Yaakov Lumer,Daniel K. Podolsky,Felix Dreisow,Stefan Nolte,Mordechai Segev,Alexander Szameit +8 more
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TLDR
This work proposes and experimentally demonstrate a photonic topological insulator free of external fields and with scatter-free edge transport—a photonic lattice exhibiting topologically protected transport of visible light on the lattice edges.Abstract:
Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on their surfaces. In two dimensions, electrons on the surface of a topological insulator are not scattered despite defects and disorder, providing robustness akin to that of superconductors. Topological insulators are predicted to have wide-ranging applications in fault-tolerant quantum computing and spintronics. Substantial effort has been directed towards realizing topological insulators for electromagnetic waves. One-dimensional systems with topological edge states have been demonstrated, but these states are zero-dimensional and therefore exhibit no transport properties. Topological protection of microwaves has been observed using a mechanism similar to the quantum Hall effect, by placing a gyromagnetic photonic crystal in an external magnetic field. But because magnetic effects are very weak at optical frequencies, realizing photonic topological insulators with scatter-free edge states requires a fundamentally different mechanism-one that is free of magnetic fields. A number of proposals for photonic topological transport have been put forward recently. One suggested temporal modulation of a photonic crystal, thus breaking time-reversal symmetry and inducing one-way edge states. This is in the spirit of the proposed Floquet topological insulators, in which temporal variations in solid-state systems induce topological edge states. Here we propose and experimentally demonstrate a photonic topological insulator free of external fields and with scatter-free edge transport-a photonic lattice exhibiting topologically protected transport of visible light on the lattice edges. Our system is composed of an array of evanescently coupled helical waveguides arranged in a graphene-like honeycomb lattice. Paraxial diffraction of light is described by a Schrodinger equation where the propagation coordinate (z) acts as 'time'. Thus the helicity of the waveguides breaks z-reversal symmetry as proposed for Floquet topological insulators. This structure results in one-way edge states that are topologically protected from scattering.read more
Citations
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Journal ArticleDOI
Observation of an unpaired photonic Dirac point
Gui-Geng Liu,Peiheng Zhou,Yihao Yang,Haoran Xue,Xin Ren,Xiao Lin,Hong-xiang Sun,Lei Bi,Yidong Chong,Baile Zhang +9 more
TL;DR: In this paper, the first unpaired Dirac point in a planar two-dimensional photonic crystal was observed, where a parity-breaking parameter was fine-tuned to a topological transition between a photonic Chern insulator and a conventional photonic insulator phase.
Book ChapterDOI
Electronic properties of carbon-based nanostructures
TL;DR: In this article, the isolation of a single graphene monolayer by mechanical exfoliation (repeated peeling or micromechanical cleavage) starting from bulk graphite has been revealed, since it was previously believed to be thermodynamically unstable.
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Realization of Weyl semimetal phases in topoelectrical circuits
TL;DR: In this paper, the authors demonstrate a simple and effective method to design and realize various Weyl semimetal (WSM) states in a three-dimensional periodic circuit lattice composed of passive electric circuit elements such as inductors and capacitors (LC).
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Experimentally Detecting Quantized Zak Phases without Chiral Symmetry in Photonic Lattices
Zhi-Qiang Jiao,Zhi-Qiang Jiao,Stefano Longhi,Stefano Longhi,Xiao-Wei Wang,Xiao-Wei Wang,Jun Gao,Jun Gao,Wen-Hao Zhou,Wen-Hao Zhou,Yao Wang,Yao Wang,Yu-Xuan Fu,Li Wang,Li Wang,Ruo-Jing Ren,Ruo-Jing Ren,Lu-Feng Qiao,Lu-Feng Qiao,Xian-Min Jin,Xian-Min Jin +20 more
TL;DR: In this paper, an extended Su-Schrieffer-Heeger model with broken chiral symmetry was realized by engineering one-dimensional zigzag photonic lattices, where the long-range hopping breaks chiral symmetries but ensures the existence of inversion symmetry.
References
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