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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Realization of Anomalous Floquet Insulators in Strongly Coupled Nanophotonic Lattices
TL;DR: This work experimentally realized Floquet topological photonic insulators using a square lattice of direct-coupled octagonal resonators to achieve strong and asymmetric couplings in each unit cell, which are necessary for realizing anomalous Floquet insulator behaviors.
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Observation of Hourglass Nodal Lines in Photonics.
Lingbo Xia,Lingbo Xia,Qinghua Guo,Biao Yang,Biao Yang,Jiaguang Han,Chao-Xing Liu,Weili Zhang,Weili Zhang,Shuang Zhang +9 more
TL;DR: The observed photonic HNL resides in a clean and large frequency interval and is immune to symmetry preserving perturbation, which provides an ideal robust platform for photonic applications, such as anomalous quantum oscillation, spontaneous emission and resonant scattering.
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Lasing from complete set of topological states in two dimensional photonic crystal structure.
TL;DR: In this paper, a tetramer composed of four identical air holes perforated into an InGaAsP multiple-quantum-well epilayer slab is used to generate hierarchical topological eigenstates with no bulk multipole moment.
Journal Article
High-harmonic generation in solids with and without topological edge states
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Second-harmonic generation via double topological valley-Hall kink modes in all-dielectric photonic crystals
TL;DR: In this paper, the second-harmonic generation (SHG) via nonlinear interaction of double topological valley-Hall kink modes in all-dielectric photonic crystals (PhCs) is demonstrated.
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