Inverse Design of Photonic Topological Insulators with Extra‐Wide Bandgaps

Chen, Yafeng; Meng, Fei; Jia, Baohua; Li, Guangyao; Huang, Xiaodong

doi:10.1002/pssr.201900175

Cited by 35 publications

(13 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A unique feature of these systems is the existence of topological protected edge states, where according to the bulk-edge correspondence principle, a ddimensional TI supports (d-1) dimensional gapless edge states. Inspired by the interesting physics and promising technological applications, the concept of TIs has been extended to classical wave systems, e.g., photonic systems [8][9][10][11][12][13][14][15][16][17]. Photonic topological insulators enable the robust manipulation of light, thus providing the possibility of novel topological photonic applications, such as non-reciprocal devices [11], pseudospin-polarized waveguides [12][13][14] and topological lasers [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Dual-Polarization Second-Order Photonic Topological Insulators

et al. 2021

Self Cite

View full text Add to dashboard Cite

Second-order photonic topological insulators that host highly localized corner states resilient to defects, are opening new routes towards developing fascinating photonic devices. However, the existing works on second-order photonic topological insulators have mainly focused on either transverse magnetic or transverse electric modes. In this paper, we propose a dual-polarization topological photonic crystal structure for both transverse magnetic and transverse electric modes through topology optimization. Simple tight-binding lattice models are constructed to reveal the topological features of the optimized photonic crystal structure in a transparent way. The optimized dual-polarization second-order photonic topological insulator hosts four groups of corner states with different profiles and eigenfrequencies for both the transverse magnetic and transverse electric modes. Moreover, the robustness of theses corner states against defects is explicitly demonstrated. Our results offer opportunities for developing polarization-independent topological photonic devices.

show abstract

Section: Introductionmentioning

confidence: 99%

Dual-Polarization Second-Order Photonic Topological Insulators

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…The inverse design problem, meaning the direct retrieval of the proper structure for the desired optical performance, requires exploration of a large degree of freedom in the design space, and hence is very challenging and timeconsuming [36,181]. Recently, topology optimization, as a large-scale computational technique employing powerful gradient-based numerical algorithms, has been applied to inversely design Dirac-like cones [36][37][38][39][40]. The topology optimization is a rule-based approach containing iterative searching steps in a case-by-case manner, usually relying on numerical simulations in each step to produce intermediate results that help to modify the searching strategy [181].…”

Section: Discussionmentioning

confidence: 99%

“…beyond the Brillouin zone center, edges and highsymmetry lines. Such accidental-degeneracy-induced Dirac cones in general can be achieved by closing band gaps at a desired k point with a band engineering method [35] or other optimization techniques [36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Hermitian and Non-Hermitian Dirac-Like Cones in Photonic and Phononic Structures

Luo

Lai

2022

Front. Phys.

View full text Add to dashboard Cite

Accidental degeneracy plays an important role in the generation of novel band dispersions. Photonic structures that exhibit an accidental Dirac-like conical dispersion at the center of the Brillouin zone can behave like a zero-index material at the Dirac-point frequency, leading to a number of unique features, such as invariant phase in space, wave tunneling, photonic doping and anti-doping, etc. Such a phenomenon has been explored in on-chip structures or three dimensions recently. The introduction of non-Hermiticity into the system via loss or gain could transform the accidental Dirac-like cone into a spawning ring of exceptional points, a complex Dirac-like cone or other unique dispersions. Similar Dirac-like cones and related physics are also observed in phononic structures. This review presents an overview of the accidental-degeneracy-induced Dirac-like cones at the center of the Brillouin zone in both photonic and phononic structures, including the fundamental physics, effective-medium description and experimental demonstration, as well as current challenges and future directions.

show abstract

“…Besides, the narrow band gap hardly produces strongly localized edge and corner states, which are obligatory for many practical applications. Therefore, there is an urgent need to formulate the design problem, which can be treated with topology optimization [21][22][23][24]. Meanwhile, topology optimization also enables to adjust the operate frequencies of edge and corners states beyond the traditional way through adjusting the size of unit cells.…”

Section: Introductionmentioning

confidence: 99%

Inverse design of higher-order photonic topological insulators

Chen

Meng

Kivshar

et al. 2020

Phys. Rev. Research

Self Cite

View full text Add to dashboard Cite

The recently discovered second-order photonic topological insulators (SPTIs) are characterized by gapped edge states and robust corner states, and they provide novel approaches to the traditional ways to manipulate light. In a general case, the overlapped band gap of nontrivial and trivial photonic crystals composing SPTIs is narrow, which barely allows for the production of strongly localized states. Here, we introduce an intelligent numerical approach for the inverse design of large classes of SPTIs with great flexibility for controlling the properties of topological edge and corner states. In the optimized designs, the overlapped band gap of the nontrivial and trivial photonic crystals substantially exceeds that of the existing SPTIs, and it enables the existence of highly localized corner and edge states with nearly flat dispersion. We design several structures supporting both topological edge and corner states at the desired frequencies. Through programming newly created SPTIs, we suggest a strategy for routing topological edge and corner states. Our findings pave the way for the development of integrated photonic devices with topological protection and innovative functionalities.

show abstract

Inverse Design of Photonic Topological Insulators with Extra‐Wide Bandgaps

Cited by 35 publications

References 62 publications

Dual-Polarization Second-Order Photonic Topological Insulators

Dual-Polarization Second-Order Photonic Topological Insulators

Hermitian and Non-Hermitian Dirac-Like Cones in Photonic and Phononic Structures

Inverse design of higher-order photonic topological insulators

Contact Info

Product

Resources

About