A silicon-on-insulator slab for topological valley transport

He, Xin‐Tao; Liang, En-Tao; Yuan, Jiang; Qiu, Hao-Yang; Chen, Xiao‐Dong; Zhao, Fuli; Dong, Jian‐Wen

doi:10.1038/s41467-019-08881-z

Cited by 491 publications

(321 citation statements)

References 55 publications

Supporting

Mentioning

316

Contrasting

Unclassified

Order By: Relevance

“…Sweeping Δ r , we obtain the phase diagram as shown in Figure c, which exhibits a topological phase transition when Δ r crosses zero . Note that our first‐principle calculations reveal that the absolute values of the valley‐dependent numbers around K/K′ valley are smaller than one‐half in our practical structure, due to the large bandgaps . However, the sign of the valley‐Chern number defined as | C V | = | C K − C K′ | will guarantee the protection of topological valley‐Hall phase, as long as the bulk states at K and K′ valleys are orthogonal to each other …”

mentioning

confidence: 91%

Valley‐Hall Photonic Topological Insulators with Dual‐Band Kink States

Chen

Zhang

et al. 2019

Advanced Optical Materials

View full text Add to dashboard Cite

Extensive researches have revealed that valley, a binary degree of freedom (DOF), can be an excellent candidate of information carrier. Recently, valley DOF is introduced into photonic systems, and several valley‐Hall photonic topological insulators (PTIs) are experimentally demonstrated. However, in the previous valley‐Hall PTIs, topological kink states only work at a single frequency band, which limits potential applications in multiband waveguides, filters, communications, and so on. To overcome this challenge, here a valley‐Hall PTI, where the topological kink states exist at two separated frequency bands, is experimentally demonstrated in a microwave substrate‐integrated circuitry. Both the simulated and experimental results demonstrate the dual‐band valley‐Hall topological kink states are robust against the sharp bends of the internal domain wall with negligible intervalley scattering. This work may pave the way for multichannel substrate‐integrated photonic devices with high efficiency and high capacity for information communications and processing.

show abstract

mentioning

confidence: 91%

Valley‐Hall Photonic Topological Insulators with Dual‐Band Kink States

Chen

Zhang

et al. 2019

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…These approaches usually require external intervention or strict parameter condition that have to sacrifice in some other important aspects, and there is still a high demand for devices with a naturally robust design. More recently, the robust waveguiding and transportation based on TES have been proposed and demonstrated in silicon platform, showing the advantages of topological design in integrated photonic devices. Therefore, it is quite possible to utilize these TESs to access the robust coupling of light between waveguides, though they were rarely studied previously.…”

Section: Introductionmentioning

confidence: 99%

Robust and Broadband Optical Coupling by Topological Waveguide Arrays

Song

Sun

Chen

et al. 2020

Laser & Photonics Reviews

View full text Add to dashboard Cite

Photonic topological states have been exploited to give rise to robust optical behaviors that are quite insensitive to local defects or perturbations, which provide a promising solution for robust photonic integrations. Specifically, for example, optical coupling between waveguides is a universal function in integrated photonics. However, the coupling performance usually suffers from high structure‐sensitivity and challenges current manufacturing for massive production. Here, the topological edge state in a finite Su–Schriffer–Heeger modeled optical waveguide array is explored and robust optical coupling (e.g., directional coupling and beam splitting) is demonstrated, which is quite insensitive to structural variations. It is experimentally proved that even a large discrepancy (21–26% structural deviation) in silicon waveguides gaps has little influence on optical coupling (>90% performance), while conventional counterparts totally break down. Moreover, thanks to such a topological design, the devices show much broader working bandwidth (≈10 times performance improvement) than the conventional ones, greatly favoring the photonic integrations. This work would inspire new families of optical devices with robust and broadband properties that can excite more interesting and useful exploration in both fields, and possibly open a new avenue toward topological devices with unique properties and functionalities.

show abstract

“…Their pseudospindependent physics may be useful for manipulation of internal degrees of freedom of light such as polarization and angular momentum.However, the experimental characterization of topological photonic structures becomes much more challenging at the nanoscale. Most implementations so far have been limited to indirect probing of topological states such as transmission spectra [11,[18][19][20], which cannot provide spatially-resolved information about the edge modes and suffer from input/output coupling losses. Other recentlydemonstrated linear approaches such as near-field imaging [21], cathodoluminescence [22], and far-field imaging [23] suffer from poor spatial resolution or small field of view, leaving the edge states almost completely hidden in the background noise.…”

mentioning

confidence: 99%

Third-Harmonic Generation in Photonic Topological Metasurfaces

et al. 2019

View full text Add to dashboard Cite

We study nonlinear effects in two-dimensional photonic metasurfaces supporting topologicallyprotected helical edge states at the nanoscale. We observe strong third-harmonic generation mediated by optical nonlinearities boosted by multipolar Mie resonances of silicon nanoparticles. Variation of the pump-beam wavelength enables independent high-contrast imaging of either bulk modes or spin-momentum-locked edge states. We demonstrate topology-driven tunable localization of the generated harmonic fields and map the pseudospin-dependent unidirectional waveguiding of the edge states bypassing sharp corners. Our observations establish dielectric metasurfaces as a promising platform for the robust generation and transport of photons in topological photonic nanostructures.Topological photonics describes optical structures with the properties analogous to electronic topological insulators [1]. These systems are distinguished by bulk band gaps that host disorder-robust states localized at edges or interfaces and provide a novel approach for designing non-reciprocal or localized modes for optical isolators, photonic-crystal waveguides, and lasers. Since the original demonstration of backscattering-immune photonic topological edge states with the use of a gyrotropic microwave photonic crystal under a strong magnetic field [2], there has been a concerted effort towards realizing topological photonics at the nanoscale. Recently suggested optical designs compatible with non-magnetic alldielectric structures [3][4][5][6][7][8] are now emerging as a promising platform for quantum and nonlinear topological photonics [9][10][11][12].Stimulated by the progress in nanofabrication techniques, a new favourable ground for topological photonics based on dielectric nanoparticles with high refractive index has recently emerged [13,14]. Strong optical resonances and low Ohmic losses make it feasible for practical implementation of topological order for light at subwavelength scales. The underlying conceptual framework is to use arrays of meta-atoms with judiciously engineered shape and lattice structure, with topologically nontrivial features arising from pseudospin degrees of freedom. It bridges fundamental physics of topological phases with resonant nanophotonics and multipolar electrodynamics [15,16]. Topological metasurfaces could form a ground for a new class of ultra-thin devices with functionalities based on novel physical principles through engineering light-matter interactions in synthetic photonic potentials [17]. Their pseudospindependent physics may be useful for manipulation of internal degrees of freedom of light such as polarization and angular momentum.However, the experimental characterization of topological photonic structures becomes much more challenging at the nanoscale. Most implementations so far have been limited to indirect probing of topological states such as transmission spectra [11,[18][19][20], which cannot provide spatially-resolved information about the edge modes and suffer from input/output coupling losses. ...

show abstract

A silicon-on-insulator slab for topological valley transport

Cited by 491 publications

References 55 publications

Valley‐Hall Photonic Topological Insulators with Dual‐Band Kink States

Valley‐Hall Photonic Topological Insulators with Dual‐Band Kink States

Robust and Broadband Optical Coupling by Topological Waveguide Arrays

Third-Harmonic Generation in Photonic Topological Metasurfaces

Contact Info

Product

Resources

About