Visualization of Higher-Order Topological Insulating Phases in Two-Dimensional Dielectric Photonic Crystals

Physical Review Letters, Journal Year: 2019, Volume and Issue: 122(23)

Published: June 14, 2019

The studies of topological phases matter have been developed from condensed physics to photonic systems, resulting in fascinating designs robust devices. Recently, higher-order insulators investigated as a novel phase beyond the conventional bulk-boundary correspondence. Previous mainly focused on multipole systems with negative coupling between lattice sites. Here we experimentally demonstrate that second-order insulating without can be realized two-dimensional dielectric crystals. We visualize both one-dimensional edge states and zero-dimensional corner by using near-field scanning technique. Our findings open new research frontiers for provide mechanism light manipulating hierarchical way.

Language: Английский

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Higher-order band topology

Nature Reviews Physics, Journal Year: 2021, Volume and Issue: 3(7), P. 520 - 532

Published: June 15, 2021

Language: Английский

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Recent advances in 2D, 3D and higher-order topological photonics

Light Science & Applications, Journal Year: 2020, Volume and Issue: 9(1)

Published: July 20, 2020

Abstract Over the past decade, topology has emerged as a major branch in broad areas of physics, from atomic lattices to condensed matter. In particular, received significant attention photonics because light waves can serve platform investigate nontrivial bulk and edge physics with aid carefully engineered photonic crystals metamaterials. Simultaneously, provides enriched that arises spin-1 vectorial electromagnetic fields. Here, we review recent progress growing field topological three parts. The first part is dedicated basics band theory introduces various two-dimensional phases. second reviews three-dimensional phases numerous approaches achieve them photonics. Last, present recently emerging fields have not yet been reviewed. This includes degeneracies nonzero dimensions, unidirectional Maxwellian spin waves, higher-order phases, stacking attain layer pseudospin. addition for realizing also discuss interaction between matter efforts towards practical applications

Language: Английский

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Photonic crystal nanocavity based on a topological corner state

Optica, Journal Year: 2019, Volume and Issue: 6(6), P. 786 - 786

Published: May 31, 2019

Topological phonics has emerged as a novel approach to engineer the flow of light and provides unprecedented means for developing diverse photonic elements, including robust optical waveguides immune structural imperfections. However, development nanoscale standing-wave cavities in topological photonics is rather slow, despite its importance when building densely-integrated integrated circuits. In this Letter, we report crystal nanocavity based on corner state, supported at 90-degrees-angled rim two dimensional crystal. A combination bulk-edge edge-corner correspondences guarantees presence higher-order state hierarchical manner. We experimentally observed mode that tightly localized space while supporting high Q factor over 2,000, verifying promise nanocavity. These results cast new way introduce nanocavities platforms.

Language: Английский

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Low-threshold topological nanolasers based on the second-order corner state

Light Science & Applications, Journal Year: 2020, Volume and Issue: 9(1)

Published: June 29, 2020

Topological lasers are immune to imperfections and disorder. They have been recently demonstrated based on many kinds of robust edge states, which mostly at the microscale. The realization 2D on-chip topological nanolasers with a small footprint, low threshold high energy efficiency has yet be explored. Here, we report first experimental demonstration nanolaser performance in photonic crystal slab. A nanocavity is formed utilizing Wannier-type 0D corner state. Lasing behaviour approximately 1 µW spontaneous emission coupling factor 0.25 observed quantum dots as active material. Such much better than that comparable conventional nanolasers. Our low-threshold will great significance development nanophotonic circuitry for manipulation photons classical regimes.

Language: Английский

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Acoustic Realization of Quadrupole Topological Insulators

Physical Review Letters, Journal Year: 2020, Volume and Issue: 124(20)

Published: May 18, 2020

A quadrupole topological insulator, being one higher-order insulator with nontrivial quantization, has been intensely investigated very recently. However, the tight-binding model proposed for such emergent insulators demands both positive and negative hopping coefficients, which imposes an obstacle in practical realizations. Here we introduce a feasible approach to design sign of acoustics, construct first acoustic that stringently emulates model. The inherent hierarchy topology experimentally confirmed by detecting responses at bulk, edge corner sample. Potential applications can be anticipated topologically robust in-gap states, as sensing energy trapping.

Language: Английский

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Topological Photonic Crystals: Physics, Designs, and Applications

Laser & Photonics Review, Journal Year: 2022, Volume and Issue: 16(4)

Published: Feb. 15, 2022

The recent research of topological photonics has not only proposed and realized novel phenomena such as one-way broadband propagation robust transport light, but also designed fabricated photonic devices with high-performance indexes which are immune to fabrication errors defects or disorders. Photonic crystals, periodic optical structures the advantages good light field confinement multiple adjusting degrees freedom, provide a powerful platform control flow light. With topology defined in reciprocal space, crystals have been widely used reveal different phases demonstrate functionalities. In this review, we present physics dimensions, models phases. design methods introduced. Furthermore, review applications passive active photonics. These researches pave way applying practical devices.

Language: Английский

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Realization of an Acoustic Third-Order Topological Insulator

Physical Review Letters, Journal Year: 2019, Volume and Issue: 122(24)

Published: June 21, 2019

The recent discovery of higher-order topological insulators (TIs) has opened new possibilities in the search for novel materials and metamaterials. Second-order TIs have been implemented two-dimensional (2D) systems exhibiting "corner states," as well three-dimensional (3D) having one-dimensional (1D) "hinge states." Third-order TIs, which states three dimensions lower than bulk (which must thus be 3D or higher), not yet reported. Here, we describe realization a third-order TI an anisotropic diamond-lattice acoustic metamaterial. band structure nontrivial topology characterized by quantized Wannier centers. By direct measurement, observe corner at two corners rhombohedronlike structure, predicted This work extends from 2D to 3D, may find applications devices.

Language: Английский

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Higher-Order Topological Insulators in Quasicrystals

Physical Review Letters, Journal Year: 2020, Volume and Issue: 124(3)

Published: Jan. 22, 2020

Current understanding of higher-order topological insulators (HOTIs) is based primarily on crystalline materials. Here, we propose that HOTIs can be realized in quasicrystals. Specifically, show two distinct types second-order (SOTIs) constructed the quasicrystalline lattices (QLs) with different tiling patterns. One derived by using a Wilson mass term to gap out edge states quantum spin Hall insulator QLs. The other quadrupole (QI) quantized moment. We reveal some unusual features corner (CSs) SOTIs. also QI simulated designed electrical circuit, where CSs identified measuring impedance resonance peak. Our findings not only extend concept into quasicrystals but provide feasible way detect property experiments.

Language: Английский

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Higher-order quantum spin Hall effect in a photonic crystal

Nature Communications, Journal Year: 2020, Volume and Issue: 11(1)

Published: July 28, 2020

Abstract The quantum spin Hall effect lays the foundation for topologically protected manipulation of waves, but is restricted to one-dimensional-lower boundaries systems and hence limits diversity integration topological photonic devices. Recently, conventional bulk-boundary correspondence band topology has been extended higher-order cases that enable explorations states with codimensions larger than one such as hinge corner states. Here, we demonstrate a in two-dimensional crystal. Owing non-trivial pseudospin-pseudospin coupling, observe directional localization photons at corners opposite pseudospin polarizations through pseudospin-momentum-locked edge resembling manner. Our work inspires an unprecedented route transport trap spinful supporting potential applications devices lasers chiral emitters.

Language: Английский

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