Dual modulation of topological edge states from two-dimensional photonic crystals with lattice shrink

2021 ◽  
pp. 2150236
Author(s):  
Xiao-Xue Li ◽  
Yun-Tuan Fang ◽  
Li-Xia Yang
Keyword(s):  
Photonic Crystals ◽  
Edge State ◽  
Wide Bandgap ◽  
Two Dimensional ◽  
Edge States ◽  
Source Position ◽  
State Structure ◽  
Intense Field ◽  
Flat Edge ◽  
Field Localization

The current topological edge states lack dynamical modulation and the intense field localization effect. To solve these problems, we construct a topological edge state structure based on two-dimensional photonic crystals with lattice shrink. Through the optimization of structure parameters, a nearly flat edge state dispersion curve occurs in a wide bandgap. The topological edge states with intense field localization take on some unique properties such that the transport directions can be controlled by both the source spin and the source position. The transport modes can be dynamically switched between the two opposite unidirectional channels just through moving the source position.

Two-dimensional Topological Photonic Crystals with Helical Edge States below the Light Line

2021 ◽  
Author(s):  
Chengkun Zhang ◽  
Hironobu Yoshimi ◽  
Yasutomo Ota ◽  
Satoshi Iwamoto
Keyword(s):  
Photonic Crystals ◽  
Two Dimensional ◽  
Edge States ◽  
Light Line

Topological Edge State in the Two-Dimensional Stampfli-Triangle Photonic Crystals

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Bei Yan ◽  
Jianlan Xie ◽  
Exian Liu ◽  
Yuchen Peng ◽  
Rui Ge ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Edge State ◽  
Two Dimensional

Fragile topology based helical edge states in two-dimensional moon-shaped photonic crystals

2020 ◽  
Vol 102 (24) ◽  
Author(s):  
Zhongfu Li ◽  
Hsun-Chi Chan ◽  
Yuanjiang Xiang
Keyword(s):  
Photonic Crystals ◽  
Two Dimensional ◽  
Edge States

TOPOLOGICAL PHOTONIC STATES

2013 ◽  
Vol 28 (02) ◽  
pp. 1441001 ◽  
Author(s):  
CHENG HE ◽  
LIANG LIN ◽  
XIAO-CHEN SUN ◽  
XIAO-PING LIU ◽  
MING-HUI LU ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Group Velocity ◽  
Time Reversal ◽  
Edge State ◽  
Time Reversal Symmetry ◽  
Edge States ◽  
Energy Bands ◽  
Integer Quantum Hall Effect ◽  
Topological States ◽  
Photonic States

As exotic phenomena in optics, topological states in photonic crystals have drawn much attention due to their fundamental significance and great potential applications. Because of the broken time-reversal symmetry under the influence of an external magnetic field, the photonic crystals composed of magneto-optical materials will lead to the degeneracy lifting and show particular topological characters of energy bands. The upper and lower bulk bands have nonzero integer topological numbers. The gapless edge states can be realized to connect two bulk states. This topological photonic states originated from the topological property can be analogous to the integer quantum Hall effect in an electronic system. The gapless edge state only possesses a single sign of gradient in the whole Brillouin zone, and thus the group velocity is only in one direction leading to the one-way energy flow, which is robust to disorder and impurity due to the nontrivial topological nature of the corresponding electromagnetic states. Furthermore, this one-way edge state would cross the Brillouin center with nonzero group velocity, where the negative-zero-positive phase velocity can be used to realize some interesting phenomena such as tunneling and backward phase propagation. On the other hand, under the protection of time-reversal symmetry, a pair of gapless edge states can also be constructed by using magnetic–electric coupling meta-materials, exhibiting Fermion-like spin helix topological edge states, which can be regarded as an optical counterpart of topological insulator originating from the spin–orbit coupling. The aim of this article is to have a comprehensive review of recent research literatures published in this emerging field of photonic topological phenomena. Photonic topological states and their related phenomena are presented and analyzed, including the chiral edge states, polarization dependent transportation, unidirectional waveguide and nonreciprocal optical transmission, all of which might lead to novel applications such as one-way splitter, optical isolator and delay line. In addition, the possible prospect and development of related topics are also discussed.

scholarly journals Bulk-edge correspondence of classical diffusion phenomena

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tsuneya Yoshida ◽  
Yasuhiro Hatsugai
Keyword(s):  
Temperature Field ◽  
Diffusion Equation ◽  
Edge State ◽  
Lattice System ◽  
Honeycomb Lattice ◽  
Two Dimensional ◽  
Winding Number ◽  
Edge States ◽  
Diffusive Dynamics ◽  
Diffusion Phenomena

AbstractWe elucidate that diffusive systems, which are widely found in nature, can be a new platform of the bulk-edge correspondence, a representative topological phenomenon. Using a discretized diffusion equation, we demonstrate the emergence of robust edge states protected by the winding number for one- and two-dimensional systems. These topological edge states can be experimentally accessible by measuring diffusive dynamics at edges. Furthermore, we discover a novel diffusion phenomenon by numerically simulating the distribution of temperatures for a honeycomb lattice system; the temperature field with wavenumber $$\pi $$ π cannot diffuse to the bulk, which is attributed to the complete localization of the edge state.

NONLOCAL RESISTANCE AND EDGE CURRENTS IN THE FRACTIONAL QUANTUM HALL REGIME

1991 ◽  
Vol 05 (24n25) ◽  
pp. 1617-1624 ◽  
Author(s):  
J.K. WANG ◽  
V.J. GOLDMAN
Keyword(s):  
Electrical Transport ◽  
Quantum Hall ◽  
Edge State ◽  
Edge States ◽  
State Structure ◽  
Electron Hole ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Quantum Hall Regime ◽  
Hall Regime

We have studied nonlocal electrical transport over macroscopic distances in the regime of the fractional quantum Hall effect (FQHE). Experiments clearly demonstrate dissipationless edge state conduction associated with the FQHE. Surprisingly, our data imply that there is no edge state conduction near ν=1/2 and on the low ν side of the ν=1 QHE state, while there is edge state conduction near ν=3/2 and on the high ν side of the ν=1 QHE state. We also observe that the electron-hole symmetry is broken for the edge states in a confined geometry. We develop a picture of edge state structure consistent with these observations.

Robust topological edge states from one-dimensional diatomic chain photonic crystals

2021 ◽  
pp. 2150146
Author(s):  
Yun-Tuan fang ◽  
Xiao-Xue Li ◽  
Li-Xia Yang
Keyword(s):  
Photonic Crystal ◽  
Photonic Crystals ◽  
Edge State ◽  
Unit Cell ◽  
Topological Phase ◽  
Edge States ◽  
One Dimensional ◽  
Diatomic Chain ◽  
Ssh Model ◽  
Unit Cell Length

The Su–Schrieffer–Heeger (SSH) model can occur in a one-dimensional (1D) diatomic chain photonic crystal (PC) in which a unit cell includes two same slabs (atoms). With different intervals of the two slabs, the two combined 1D PCs can support topological edge states in all photonic boundary bandgaps. These topological edge states come from the inversion of topological phase of the bands through the band folding effect. When the sum of the two atom intervals in the two different 1D PCs equals to the unit cell length, these edge state frequencies keep invariant.

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