Creating higher-order topological phases using synthetic dimensions in dynamically modulated ring resonators

2020 ◽  
Author(s):  
Avik Dutt ◽  
Momchil Minkov ◽  
Ian A. Williamson ◽  
Shanhui Fan
Keyword(s):  
Higher Order ◽  
Ring Resonators ◽  
Topological Phases

scholarly journals Non-Hermitian route to higher-order topology in an acoustic crystal

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
He Gao ◽  
Haoran Xue ◽  
Zhongming Gu ◽  
Tuo Liu ◽  
Jie Zhu ◽  
...  
Keyword(s):  
Higher Order ◽  
Order Topology ◽  
Topological Phases ◽  
Edge States ◽  
Experimental Realization ◽  
Artificial Materials ◽  
Intrinsic Loss ◽  
Topological Phases Of Matter ◽  
Hierarchical Features ◽  
Nontrivial Topology

AbstractTopological phases of matter are classified based on their Hermitian Hamiltonians, whose real-valued dispersions together with orthogonal eigenstates form nontrivial topology. In the recently discovered higher-order topological insulators (TIs), the bulk topology can even exhibit hierarchical features, leading to topological corner states, as demonstrated in many photonic and acoustic artificial materials. Naturally, the intrinsic loss in these artificial materials has been omitted in the topology definition, due to its non-Hermitian nature; in practice, the presence of loss is generally considered harmful to the topological corner states. Here, we report the experimental realization of a higher-order TI in an acoustic crystal, whose nontrivial topology is induced by deliberately introduced losses. With local acoustic measurements, we identify a topological bulk bandgap that is populated with gapped edge states and in-gap corner states, as the hallmark signatures of hierarchical higher-order topology. Our work establishes the non-Hermitian route to higher-order topology, and paves the way to exploring various exotic non-Hermiticity-induced topological phases.

scholarly journals Topological holographic quench dynamics in a synthetic frequency dimension

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Danying Yu ◽  
Bo Peng ◽  
Xianfeng Chen ◽  
Xiong-Jun Liu ◽  
Luqi Yuan
Keyword(s):  
Quantum Dynamics ◽  
Dimensional Space ◽  
Dynamical Evolution ◽  
Spin Model ◽  
Ring Resonators ◽  
Nonequilibrium Dynamics ◽  
Topological Phases ◽  
Time Dimension ◽  
Efficient Scheme ◽  
Quench Dynamics

AbstractThe notion of topological phases extended to dynamical systems stimulates extensive studies, of which the characterization of nonequilibrium topological invariants is a central issue and usually necessitates the information of quantum dynamics in both the time and momentum dimensions. Here, we propose the topological holographic quench dynamics in synthetic dimension, and also show it provides a highly efficient scheme to characterize photonic topological phases. A pseudospin model is constructed with ring resonators in a synthetic lattice formed by frequencies of light, and the quench dynamics is induced by initializing a trivial state, which evolves under a topological Hamiltonian. Our key prediction is that the complete topological information of the Hamiltonian is encoded in quench dynamics solely in the time dimension, and is further mapped to lower-dimensional space, manifesting the holographic features of the dynamics. In particular, two fundamental time scales emerge in the dynamical evolution, with one mimicking the topological band on the momentum dimension and the other characterizing the residue time evolution of the state after the quench. For this, a universal duality between the quench dynamics and the equilibrium topological phase of the spin model is obtained in the time dimension by extracting information from the field evolution dynamics in modulated ring systems in simulations. This work also shows that the photonic synthetic frequency dimension provides an efficient and powerful way to explore the topological nonequilibrium dynamics.

scholarly journals Higher-order Floquet topological phases with corner and bulk bound states

2019 ◽  
Vol 100 (8) ◽  
Author(s):  
Martin Rodriguez-Vega ◽  
Abhishek Kumar ◽  
Babak Seradjeh
Keyword(s):  
Bound States ◽  
Higher Order ◽  
Topological Phases

scholarly journals Coupling Schemes in Terahertz Planar Metamaterials

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Dibakar Roy Chowdhury ◽  
Ranjan Singh ◽  
Antoinette J. Taylor ◽  
Hou-Tong Chen ◽  
Weili Zhang ◽  
...  
Keyword(s):  
Resonance Line ◽  
Ring Resonator ◽  
Near Field ◽  
Split Ring Resonator ◽  
Higher Order ◽  
Ring Resonators ◽  
Split Ring ◽  
Split Ring Resonators ◽  
Sensing Applications ◽  
Lattice Mode

We present a review of the different coupling schemes in a planar array of terahertz metamaterials. The gap-to-gap near-field capacitive coupling between split-ring resonators in a unit cell leads to either blue shift or red shift of the fundamental inductive-capacitive (LC) resonance, depending on the position of the split gap. The inductive coupling is enhanced by decreasing the inter resonator distance resulting in strong blue shifts of theLCresonance. We observe theLCresonance tuning only when the split-ring resonators are in close proximity of each other; otherwise, they appear to be uncoupled. Conversely, the higher-order resonances are sensitive to the smallest change in the inter particle distance or split-ring resonator orientation and undergo tremendous resonance line reshaping giving rise to a sharp subradiant resonance mode which produces hot spots useful for sensing applications. Most of the coupling schemes in a metamaterial are based on a near-field effect, though there also exists a mechanism to couple the resonators through the excitation of lowest-order lattice mode which facilitates the long-range radiative or diffractive coupling in the split-ring resonator plane leading to resonance line narrowing of the fundamental as well as the higher order resonance modes.

scholarly journals Time-periodic corner states from Floquet higher-order topology

2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Weiwei Zhu ◽  
Haoran Xue ◽  
Jiangbin Gong ◽  
Yidong Chong ◽  
Baile Zhang
Keyword(s):  
Three Dimensional ◽  
Higher Order ◽  
Topological Phases ◽  
Time Dynamics ◽  
Topological States ◽  
Acoustic Lattice ◽  
Static Systems ◽  
Time Invariant ◽  
Time Periodic ◽  
Spatial Axis

AbstractThe recent discoveries of higher-order topological insulators (HOTIs) have shifted the paradigm of topological materials, previously limited to topological states at boundaries of materials, to include topological states at boundaries of boundaries, such as corners. So far, all HOTI realisations have been based on static systems described by time-invariant Hamiltonians, without considering the time-variant situation. There is growing interest in Floquet systems, in which time-periodic driving can induce unconventional phenomena such as Floquet topological phases and time crystals. Recent theories have attempted to combine Floquet engineering and HOTIs, but there has been no experimental realisation so far. Here we report on the experimental demonstration of a two-dimensional (2D) Floquet HOTI in a three-dimensional (3D) acoustic lattice, with modulation along a spatial axis serving as an effective time-dependent drive. Acoustic measurements reveal Floquet corner states with double the period of the underlying drive; these oscillations are robust, like time crystal modes, except that the robustness arises from topological protection. This shows that space-time dynamics can induce anomalous higher-order topological phases unique to Floquet systems.

Observation of higher order radial modes in atomic layer deposition reinforced rolled-up microtube ring resonators

2014 ◽  
Vol 39 (21) ◽  
pp. 6335 ◽  
Author(s):  
Jens Trommer ◽  
Stefan Böttner ◽  
Shilong Li ◽  
Suwit Kiravittaya ◽  
Matthew R. Jorgensen ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Higher Order ◽  
Ring Resonators ◽  
Layer Deposition
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