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Rui-Xin Wu

Bio: Rui-Xin Wu is an academic researcher from Nanjing University. The author has contributed to research in topics: Photonic crystal & Electromagnetic radiation. The author has an hindex of 9, co-authored 50 publications receiving 730 citations.


Papers
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Journal ArticleDOI
TL;DR: This experimental demonstration of self-guiding electromagnetic edge states existing along the zigzag edge of a honeycomb magnetic photonic crystal allows for the unidirectional transport of electromagnetic energy without requiring an ancillary cladding layer.
Abstract: We present an experimental demonstration of self-guiding electromagnetic edge states existing along the zigzag edge of a honeycomb magnetic photonic crystal. These edge states are shown to possess unidirectional propagation characteristics that are robust against various types of defects and obstacles. In particular, they allow for the unidirectional transport of electromagnetic energy without requiring an ancillary cladding layer.

451 citations

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TL;DR: It is demonstrated that concurrent wavevector space and real-space topology can lead to a topologically protected zero-dimensional cavity mode in a two-dimensional photonic crystal, which is invaluable for fundamental physics and various applications in photonics.
Abstract: Topological insulators have unconventional gapless edge states where disorder-induced back-scattering is suppressed. In photonics, such edge states lead to unidirectional waveguides which are useful for integrated photonic circuitry. Cavity modes, another type of fundamental component in photonic chips, however, are not protected by band topology because of their lower dimensions. Here we demonstrate that concurrent wavevector space and real-space topology, dubbed as dual-topology, can lead to light-trapping in lower dimensions. The resultant photonic-bound state emerges as a Jackiw–Rebbi soliton mode localized on a dislocation in a two-dimensional photonic crystal, as proposed theoretically and discovered experimentally. Such a strongly confined cavity mode is found to be robust against perturbations. Our study unveils a mechanism for topological light-trapping in lower dimensions, which is invaluable for fundamental physics and various applications in photonics. Although topological confinement of waves to the edges is common, lower-dimensional wave confinement is scarce. Here, Li et al. demonstrate that concurrent wavevector and real-space topology can lead to a topologically protected zero-dimensional cavity mode in a two-dimensional photonic crystal.

117 citations

Journal ArticleDOI
Yan Yang, Yin Poo, Rui-Xin Wu, Yan Gu, Ping Chen 
TL;DR: In this paper, the authors experimentally demonstrate that electromagnetic waves in the waveguide comprising gyromagnetic photonic crystals and a metal cladding are robust one-way slow wave in the frequency range of the chiral edge states of GMPC.
Abstract: We experimentally demonstrate that electromagnetic waves in the waveguide comprising gyromagnetic photonic crystals (GMPCs) and a metal cladding are robust one-way slow waves in the frequency range of the chiral edge states of GMPC. Measured with phase shift technique in microwave regime, the group velocity of the wave could be one order of magnitude smaller than the speed of light with group index up to 15.6. The one-way wave with much slower group velocity is shown by retailoring the waveguide further. This waveguide provides a potential way to realize robust slow-light transmission lines in electromagnetic or optical systems.

73 citations

Journal ArticleDOI
TL;DR: In this paper, the photonic band gaps (PBGs) of two dimensional magnetic pho-tonic crystals (MPCs) consisting of arrays of magnetic cylinders are studied.
Abstract: Bartol Research Institute, University of Delaware, Newark, Delaware 19716, USA(Dated: May 8, 2008)We identify different types of the photonic band gaps (PBGs) of two dimensional magnetic pho-tonic crystals (MPCs) consisting of arrays of magnetic cylinders and study the different tunability(by an external static magnetic field) of these PBGs One type of the band gaps comes from in-finitely degenerate flat bands and is closely related to those in the study of plasmonics In addition,such PBGs are magnetically tunable and robust against position disorder We calcualte the trans-mission of the PBG’s and found excellent agreement with the results of the photonic band structurecalculation Positional disorder of the lattice structure affects the different types of PBGs differently

64 citations

Journal ArticleDOI
TL;DR: In this paper, a topological valley phase transition between different valley Chern numbers (from one to three) is realized by changing the configuration of the unit cell, which can guide wave propagation robustly along a sharply bent domain wall.
Abstract: The recent realizations of a topological valley phase in a photonic crystal, an analog of gapped valleytronic materials in an electronic system, are limited to the valley Chern number of one. In this paper, we present a type of valley phase that can have a large valley Chern number of two or three. The valley phase transitions between the different valley Chern numbers (from one to three) are realized by changing the configuration of the unit cell. We demonstrate that these topological phases can guide the wave propagation robustly along a sharply bent domain wall. We believe our results are promising for the exploration of new topological phenomena in photonic systems.

32 citations


Cited by
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Journal ArticleDOI
TL;DR: Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light as mentioned in this paper, which holds great promise for applications.
Abstract: Topological photonics is a rapidly emerging field of research in which geometrical and topological ideas are exploited to design and control the behavior of light. Drawing inspiration from the discovery of the quantum Hall effects and topological insulators in condensed matter, recent advances have shown how to engineer analogous effects also for photons, leading to remarkable phenomena such as the robust unidirectional propagation of light, which hold great promise for applications. Thanks to the flexibility and diversity of photonics systems, this field is also opening up new opportunities to realize exotic topological models and to probe and exploit topological effects in new ways. This article reviews experimental and theoretical developments in topological photonics across a wide range of experimental platforms, including photonic crystals, waveguides, metamaterials, cavities, optomechanics, silicon photonics, and circuit QED. A discussion of how changing the dimensionality and symmetries of photonics systems has allowed for the realization of different topological phases is offered, and progress in understanding the interplay of topology with non-Hermitian effects, such as dissipation, is reviewed. As an exciting perspective, topological photonics can be combined with optical nonlinearities, leading toward new collective phenomena and novel strongly correlated states of light, such as an analog of the fractional quantum Hall effect.

3,052 citations

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TL;DR: It is shown that metacrystals-superlattices of metamaterials with judiciously designed properties-provide a platform for designing topologically non-trivial photonic states, similar to those identified for condensed-matter topological insulators.
Abstract: Recent progress in understanding the topological properties of condensed matter has led to the discovery of time-reversal-invariant topological insulators. A remarkable and useful property of these materials is that they support unidirectional spin-polarized propagation at their surfaces. Unfortunately topological insulators are rare among solid-state materials. Using suitably designed electromagnetic media (metamaterials) we theoretically demonstrate a photonic analogue of a topological insulator. We show that metacrystals-superlattices of metamaterials with judiciously designed properties-provide a platform for designing topologically non-trivial photonic states, similar to those that have been identified for condensed-matter topological insulators. The interfaces of the metacrystals support helical edge states that exhibit spin-polarized one-way propagation of photons, robust against disorder. Our results demonstrate the possibility of attaining one-way photon transport without application of external magnetic fields or breaking of time-reversal symmetry. Such spin-polarized one-way transport enables exotic spin-cloaked photon sources that do not obscure each other.

1,509 citations

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TL;DR: In this paper, a review of recent theoretical and experimental advances in the fundamental understanding and active control of quantum fluids of light in nonlinear optical systems is presented, from the superfluid flow around a defect at low speeds to the appearance of a Mach-Cherenkov cone in a supersonic flow, to the hydrodynamic formation of topological excitations such as quantized vortices and dark solitons at the surface of large impenetrable obstacles.
Abstract: This article reviews recent theoretical and experimental advances in the fundamental understanding and active control of quantum fluids of light in nonlinear optical systems. In the presence of effective photon-photon interactions induced by the optical nonlinearity of the medium, a many-photon system can behave collectively as a quantum fluid with a number of novel features stemming from its intrinsically nonequilibrium nature. A rich variety of recently observed photon hydrodynamical effects is presented, from the superfluid flow around a defect at low speeds, to the appearance of a Mach-Cherenkov cone in a supersonic flow, to the hydrodynamic formation of topological excitations such as quantized vortices and dark solitons at the surface of large impenetrable obstacles. While the review is mostly focused on a specific class of semiconductor systems that have been extensively studied in recent years (planar semiconductor microcavities in the strong light-matter coupling regime having cavity polaritons as elementary excitations), the very concept of quantum fluids of light applies to a broad spectrum of systems, ranging from bulk nonlinear crystals, to atomic clouds embedded in optical fibers and cavities, to photonic crystal cavities, to superconducting quantum circuits based on Josephson junctions. The conclusive part of the article is devoted to a review of the future perspectives in the direction of strongly correlated photon gases and of artificial gauge fields for photons. In particular, several mechanisms to obtain efficient photon blockade are presented, together with their application to the generation of novel quantum phases.

1,469 citations

Journal ArticleDOI
TL;DR: In this paper, the authors show that a judicious choice of the metamaterial parameters can create photonic phases that support a pair of helical edge states, and these edge states enable one-way photonic transport that is robust against disorder.
Abstract: Recent progress in understanding the topological properties of condensed matter has led to the discovery of time-reversal invariant topological insulators. Because of limitations imposed by nature, topologically non-trivial electronic order seems to be uncommon except in small-band-gap semiconductors with strong spin-orbit interactions. In this Article we show that artificial electromagnetic structures, known as metamaterials, provide an attractive platform for designing photonic analogues of topological insulators. We demonstrate that a judicious choice of the metamaterial parameters can create photonic phases that support a pair of helical edge states, and that these edge states enable one-way photonic transport that is robust against disorder.

938 citations

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TL;DR: In this paper, the authors develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids.
Abstract: The manipulation of acoustic wave propagation in fluids has numerous applications, including some in everyday life Acoustic technologies frequently develop in tandem with optics, using shared concepts such as waveguiding and metamedia It is thus noteworthy that an entirely novel class of electromagnetic waves, known as topological edge states, has recently been demonstrated These are inspired by the electronic edge states occurring in topological insulators, and possess a striking and technologically promising property: the ability to travel in a single direction along a surface without backscattering, regardless of the existence of defects or disorder Here, we develop an analogous theory of topological fluid acoustics, and propose a scheme for realizing topological edge states in an acoustic structure containing circulating fluids The phenomenon of disorder-free one-way sound propagation, which does not occur in ordinary acoustic devices, may have novel applications for acoustic isolators, modulators, and transducers

918 citations