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
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Observation of a symmetry-protected topological phase of interacting bosons with Rydberg atoms
Sylvain de Léséleuc,Vincent Lienhard,Pascal Scholl,Daniel Barredo,Sebastian Mario Weber,Nicolai Lang,Hans Peter Büchler,Thierry Lahaye,Antoine Browaeys +8 more
TL;DR: The experimental realization of a symmetry-protected topological phase of interacting bosons in a one-dimensional lattice is reported and a robust ground state degeneracy attributed to protected zero-energy edge states is demonstrated.
Journal ArticleDOI
Symmetry-protected topological photonic crystal in three dimensions
TL;DR: In this paper, a photonic analogue of a three-dimensional solid-state topological insulator is proposed, where the symmetries may protect single Dirac cones on the surface of a photonics crystal.
Journal ArticleDOI
Higher-order topological states in photonic kagome crystals with long-range interactions
Mengyao Li,Mengyao Li,Dmitry Zhirihin,Dmitry Zhirihin,Maxim A. Gorlach,Xiang Ni,Xiang Ni,Dmitry Filonov,Alexey P. Slobozhanyuk,Andrea Alù,Andrea Alù,Alexander B. Khanikaev,Alexander B. Khanikaev +12 more
TL;DR: In this article, a photonic higher-order topological insulator (HOTI) with kagome lattice exhibits topological bulk polarization, leading to the emergence of one-dimensional edge states, as well as higherorder zero-dimensional states confined to the corners of the structure.
Journal ArticleDOI
Topological Polaritons
TL;DR: In this article, it was shown that mixing single photons with excitons can result in new topological polaritonic states, or topolaritons, which can be obtained from spin-orbit coupling in the electronic system and an applied Zeeman field.
Journal ArticleDOI
Universal spin-momentum locking of evanescent waves
Todd Van Mechelen,Zubin Jacob +1 more
TL;DR: In this paper, it was shown that the direction of momentum fundamentally locks the polarization of evanescent electromagnetic waves, which is called spin-momentum locking, and the authors trace the origin of this phenomenon to complex dispersion and causality requirements on evanescence waves.
References
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