Realization of Anomalous Floquet Insulators in Strongly Coupled Nanophotonic Lattices

Afzal, Shirin; Zimmerling, Tyler J.; Yang, Ren; Perron, David; Van, Vien

doi:10.1103/physrevlett.124.253601

Cited by 72 publications

(49 citation statements)

References 30 publications

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“…1). The wave propagation in the infinite network can be described by a Bloch eigenproblem, which considers the scattering at the nodes, described by a 6 × 6 unitary matrix S(k), and also involves the bidirectional phase delay φ induced by the links: So far, topological unitary scattering wave networks 6,30-34 have only been implemented in reciprocal systems 7,[35][36][37] exploiting two time-reversed subspaces that are never genuinely decoupled. On the contrary, our non-reciprocal scattering network is formally analogous to a rigorously oriented kagome graph (see Supplementary Information), described by a unitary matrix 33 S(k), which can be mapped 38 onto the Floquet eigenproblem of a periodically driven lattice [39][40][41][42][43][44][45] , with the angle variable φ taking the role of the quasi-energy.…”

Section: Articlementioning

confidence: 99%

“…The main difference is that the low-reflection case has edge modes in every quasi-energy bandgap, whereas at high reflection, they are found only in bandgaps of type 1. This low-|R| behaviour is the hallmark of anomalous Floquet insulators 33,35,42,45 (AFI), which possess topological edge states despite the Chern number of all surrounding bands being zero. In contrast, the high-reflection case corresponds to the Chern insulator (CI).…”

Section: Chern and Anomalous Phasesmentioning

confidence: 99%

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Superior robustness of anomalous non-reciprocal topological edge states

Zhang

Delplace

Fleury

2021

Nature

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Robustness against disorder and defects is a pivotal advantage of topological systems1, manifested by the absence of electronic backscattering in the quantum-Hall2 and spin-Hall effects3, and by unidirectional waveguiding in their classical analogues4,5. Two-dimensional (2D) topological insulators4–13, in particular, provide unprecedented opportunities in a variety of fields owing to their compact planar geometries, which are compatible with the fabrication technologies used in modern electronics and photonics. Among all 2D topological phases, Chern insulators14–25 are currently the most reliable designs owing to the genuine backscattering immunity of their non-reciprocal edge modes, brought via time-reversal symmetry breaking. Yet such resistance to fabrication tolerances is limited to fluctuations of the same order of magnitude as their bandgap, limiting their resilience to small perturbations only. Here we investigate the robustness problem in a system where edge transmission can survive disorder levels with strengths arbitrarily larger than the bandgap—an anomalous non-reciprocal topological network. We explore the general conditions needed to obtain such an unusual effect in systems made of unitary three-port non-reciprocal scatterers connected by phase links, and establish the superior robustness of anomalous edge transmission modes over Chern ones to phase-link disorder of arbitrarily large values. We confirm experimentally the exceptional resilience of the anomalous phase, and demonstrate its operation in various arbitrarily shaped disordered multi-port prototypes. Our results pave the way to efficient, arbitrary planar energy transport on 2D substrates for wave devices with full protection against large fabrication flaws or imperfections.

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Section: Articlementioning

confidence: 99%

Section: Chern and Anomalous Phasesmentioning

confidence: 99%

Superior robustness of anomalous non-reciprocal topological edge states

Zhang

Delplace

Fleury

2021

Nature

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“…The anomalous Floquet topological phase was scaled up to telecom wavelengths by Afzal et al [83] using the silicon photonic resonator lattice shown in Figure 4. The main distinguishing feature compared to previous observations of quantum Hall edge states is the presence of edge states in all of the array's band gaps.…”

Section: Topological Coupled Resonator Latticesmentioning

confidence: 99%

Topological phases in ring resonators: recent progress and future prospects

Leykam

Yuan

2020

Nanophotonics

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Topological photonics has emerged as a novel paradigm for the design of electromagnetic systems from microwaves to nanophotonics. Studies to date have largely focused on the demonstration of fundamental concepts, such as nonreciprocity and waveguiding protected against fabrication disorder. Moving forward, there is a pressing need to identify applications where topological designs can lead to useful improvements in device performance. Here, we review applications of topological photonics to ring resonator–based systems, including one- and two-dimensional resonator arrays, and dynamically modulated resonators. We evaluate potential applications such as quantum light generation, disorder-robust delay lines, and optical isolation, as well as future research directions and open problems that need to be addressed.

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“…One of the key advantages of this experimental platform is the possibility of imaging the excited energies during the dynamics, allowing a direct observation of the linear and nonlinear lattice spectrum [17]. Another -completely -different photonic lattice setup consists of coupled octagon resonators, which strongly couple to each other forming nanophotonic lattice structures [18]. There, every unit cell is formed by several resonators, allowing the emulation of periodically driven systems and the study of associated topological properties.…”

Section: Introductionmentioning

confidence: 99%

Photonic flat band dynamics

Poblete

2021

Advances in Physics: X

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During the last decades, researchers of different scientific areas have investigated several systems and materials to suggest new ways of transporting and localizing light. These problems are probably main goals in any search for new configurations and new emerging properties, independently of the degree of complexity of suggested methods. Fortunately, fabrication techniques in photonics have consolidated during the last decades, allowing the experimental implementation of different theoretical ideas which were neither tested nor validated. Specifically, we will focus on recent advances in the implementation of Flat Band (FB) photonic systems. FB periodical structures have at least two bands in their linear spectrum, with one of them completely flat. This implies the emergence of linear photonic states which are completely localized in space and that can be located in different regions across the lattice. This localization occurs as a result of destructive interference, what naturally depends on the particular lattice geometry. In addition, flat band systems also posses dispersive states which make possible the observation of ballistic transport as well. Therefore, FB photonic lattices constitute an unique platform for studying localization and transport, without requiring the inclusion of any sophisticated interaction/effect, rather a smart and simple geometry.

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Realization of Anomalous Floquet Insulators in Strongly Coupled Nanophotonic Lattices

Cited by 72 publications

References 30 publications

Superior robustness of anomalous non-reciprocal topological edge states

Superior robustness of anomalous non-reciprocal topological edge states

Topological phases in ring resonators: recent progress and future prospects

Photonic flat band dynamics

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