scispace - formally typeset
Open AccessJournal ArticleDOI

Photonic Floquet topological insulators

Reads0
Chats0
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
More filters
Journal ArticleDOI

Higher-Order Topological States in Surface-Wave Photonic Crystals.

TL;DR: A planar surface‐wave photonic crystal realization of 2D higher‐order topological insulators is demonstrated experimentally, which provides a route toward robust cavity modes for scalable compact photonic devices.
Journal ArticleDOI

Symmetry Breaking in Photonic Crystals: On-Demand Dispersion from Flatband to Dirac Cones

TL;DR: It is shown that breaking symmetry enables an on-demand tuning of the local density of states of the same photonic band from zero (Dirac cone dispersion) to infinity (flatband dispersion), as well as any constant density over an adjustable spectral range.
Journal ArticleDOI

Ultrafast preparation and detection of ring currents in single atoms

TL;DR: In this paper, the authors measured how the transmission probability through a rotating tunnel depends on the sign of the magnetic quantum number m of the electron and thus on the initial direction of rotation of its quantum phase.
Journal ArticleDOI

Quarter-flux Hofstadter lattice in a qubit-compatible microwave cavity array

TL;DR: In this paper, a tunnel-coupled, time-reversal-broken microwave cavities that are both low loss and compatible with Josephson-junction-mediated interactions are presented.
Journal ArticleDOI

Lasing at K Points of a Honeycomb Plasmonic Lattice.

TL;DR: This work identifies the lasing mode as one of the singlets with an energy minimum at the K point enabling feedback, and offers prospects for studies of topological lasing in radiatively coupled systems.
References
More filters
Journal ArticleDOI

Two-dimensional gas of massless Dirac fermions in graphene

TL;DR: This study reports an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation and reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions.
Journal ArticleDOI

Colloquium: Topological insulators

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.
Journal ArticleDOI

Quantum spin Hall effect in graphene

TL;DR: Graphene is converted from an ideal two-dimensional semimetallic state to a quantum spin Hall insulator and the spin and charge conductances in these edge states are calculated and the effects of temperature, chemical potential, Rashba coupling, disorder, and symmetry breaking fields are discussed.
Journal ArticleDOI

New Method for High-Accuracy Determination of the Fine-Structure Constant Based on Quantized Hall Resistance

TL;DR: In this article, the Hall voltage of a two-dimensional electron gas, realized with a silicon metal-oxide-semiconductor field effect transistor, was measured and it was shown that the Hall resistance at particular, experimentally well-defined surface carrier concentrations has fixed values which depend only on the fine-structure constant and speed of light, and is insensitive to the geometry of the device.
Journal ArticleDOI

Quantized Hall conductance in a two-dimensional periodic potential

TL;DR: In this article, the Hall conductance of a two-dimensional electron gas has been studied in a uniform magnetic field and a periodic substrate potential, where the Kubo formula is written in a form that makes apparent the quantization when the Fermi energy lies in a gap.
Related Papers (5)