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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Particlelike Behavior of Topological Defects in Linear Wave Packets in Photonic Graphene.
Zhaoyang Zhang,Feng Li,Feng Li,Guillaume Malpuech,Yiqi Zhang,O. Bleu,Sergei V. Koniakhin,Changbiao Li,Yanpeng Zhang,Min Xiao,Min Xiao,Dmitry Solnyshkov +11 more
TL;DR: This work studies the formation, evolution, and interaction of optical vortices in wave packets at the Dirac point in photonic graphene, and shows that while their exact behavior goes beyond theDirac equation and requires a full account of the lattice properties, it can be still approximately described by an effective theory.
Journal ArticleDOI
Reconfigurable topological photonic crystal
TL;DR: In this paper, the authors demonstrate dynamic control of topological edge states by modifying the refractive index of a liquid crystal background medium, while preserving the topological order of the system.
Journal ArticleDOI
Broadband topological slow light through higher momentum-space winding
TL;DR: It is shown theoretically that this can be circumvented via an edge termination that causes the edge state to wind many times around the Brillouin zone, making it both slow and broadband.
Journal ArticleDOI
Observation of valley-selective microwave transport in photonic crystals
TL;DR: In this paper, the authors present an experimental observation of the intriguing valley transport for microwaves in photonic crystals, including the bulk valley transport and the valley-projected edge modes along the interface separating different photonic insulating phases.
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Experimental Realization of a Reflections-Free Compact Delay Line Based on a Photonic Topological Insulator
TL;DR: In this paper, a photonic delay line based on topologically protected surface electromagnetic waves (TPSWs) between two photonic topological insulators (PTIs) is demonstrated.
References
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