Geometric phase ≈ Geometric phase
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Fundamentals and Applications of Metasurfaces Open
Metasurfaces have become a rapidly growing field of research in recent years due to their exceptional abilities in light manipulation and versatility in ultrathin optical applications. They also significantly benefit from their simplified …
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Experimental reconstruction of the Berry curvature in a Floquet Bloch band Open
Cold atoms do geometry Electrons in solids populate energy bands, which can be simulated in cold atom systems using optical lattices. The geometry of the corresponding wave functions determines the topological properties of the system, but…
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Novel Topological Phase with a Zero Berry Curvature Open
We present a two-dimensional (2D) lattice model that exhibits a nontrivial topological phase in the absence of the Berry curvature. Instead, the Berry connection provides the topological nontrivial phase in the model, whose integration ove…
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Topological Exciton Bands in Moiré Heterojunctions Open
Moiré patterns are common in van der Waals heterostructures and can be used to apply periodic potentials to elementary excitations. We show that the optical absorption spectrum of transition metal dichalcogenide bilayers is profoundly alte…
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Magnetism in curved geometries Open
Extending planar two-dimensional structures into the three-dimensional space has become a general trend in multiple disciplines, including electronics, photonics, plasmonics and magnetics. This approach provides means to modify conventiona…
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Chiral Quasi-Bound States in the Continuum Open
Quasi-bound states in the continuum (QBICs) are Fano resonant states with long optical lifetimes controlled by symmetry-breaking perturbations. While conventional Fano responses are limited to linear polarizations and do not support tailor…
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Weyl Metals Open
Weyl metal is the first example of a conducting material with a nontrivial electronic structure topology, making it distinct from an ordinary metal. Unlike in insulators, the nontrivial topology is not related to invariants associated with…
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A Fully Phase‐Modulated Metasurface as An Energy‐Controllable Circular Polarization Router Open
Geometric metasurfaces primarily follow the physical mechanism of Pancharatnam–Berry (PB) phases, empowering wavefront control of cross‐polarized reflective/transmissive light components. However, inherently accompanying the cross‐polarize…
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Photonic crystals possessing multiple Weyl points and the experimental observation of robust surface states Open
Weyl points, as monopoles of Berry curvature in momentum space, have captured much attention recently in various branches of physics. Realizing topological materials that exhibit such nodal points is challenging and indeed, Weyl points hav…
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Transport of Topological Semimetals Open
Three-dimensional (3D) topological semimetals represent a new class of topological matters. The study of this family of materials has been at the frontiers of condensed matter physics, and many breakthroughs have been made. Several topolog…
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Band geometry, Berry curvature, and superfluid weight Open
| openaire: EC/FP7/340748/EU//CODE | openaire: EC/H2020/702281/EU//FLATOPS
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Multifunctional interleaved geometric-phase dielectric metasurfaces Open
Shared-aperture technology for multifunctional planar systems, performing several simultaneous tasks, was first introduced in the field of radar antennas. In photonics, effective control of the electromagnetic response can be achieved by a…
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Gyrotropic Magnetic Effect and the Magnetic Moment on the Fermi Surface Open
The current density j^{B} induced in a clean metal by a slowly-varying magnetic field B is formulated as the low-frequency limit of natural optical activity, or natural gyrotropy. Working with a multiband Pauli Hamiltonian, we obtain from …
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Generalized Pancharatnam-Berry Phase in Rotationally Symmetric Meta-Atoms Open
Pancharatnam-Berry geometric phase has attracted enormous interest in subwavelength optics and electromagnetics during the past several decades. Traditional theory predicts that the geometric phase is equal to twice the rotation angle of a…
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Topological nodal-line semimetals in alkaline-earth stannides, germanides, and silicides Open
Based on first-principles calculations and an effective Hamiltonian analysis,\nwe systematically investigate the electronic and topological properties of\nalkaline-earth compounds $AX_2$ ($A$=Ca, Sr, Ba; $X$=Si, Ge, Sn). Taking\nBaSn$_2$ a…
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Berry curvature dipole in Weyl semimetal materials: An <i>ab initio</i> study Open
Noncentrosymmetric metals are anticipated to exhibit a $dc$ photocurrent in\nthe nonlinear optical response caused by the Berry curvature dipole in momentum\nspace. Weyl semimetals (WSMs) are expected to be excellent candidates for\nobserv…
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Plasmonic Chiral Nanostructures: Chiroptical Effects and Applications Open
The plasmonic chiroptical effect has been used to manipulate chiral states of light, where the strong field enhancement and light localization in metallic nanostructures can amplify the chiroptical response. Moreover, in metamaterials, the…
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All-dielectric planar chiral metasurface with gradient geometric phase Open
Planar optical chirality of a metasurface measures its differential response between left and right circularly polarized (CP) lights and governs the asymmetric transmission of CP lights. In 2D ultra-thin plasmonic structures the circular d…
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Berry curvature dipole current in the transition metal dichalcogenides family Open
We study the quantum nonlinear Hall effect in two-dimensional materials with\ntime-reversal symmetry. When only one mirror line exists, a transverse charge\ncurrent occurs in second-order response to an external electric field, as a\nresul…
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Dynamic phase assembled terahertz metalens for reversible conversion between linear polarization and arbitrary circular polarization Open
If a metalens integrates the circular polarization (CP) conversion function, the focusing lens together with circular-polarizing lens (CPL) in traditional cameras may be replaced by a metalens. However, in terahertz (THz) band, the reporte…
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Microscopic theory for the light-induced anomalous Hall effect in graphene Open
We employ a quantum Liouville equation with relaxation to model the recently observed anomalous Hall effect in graphene irradiated by an ultrafast pulse of circularly polarized light. In the weak-field regime, we demonstrate that the Hall …
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Plug-and-Play Approach to Nonadiabatic Geometric Quantum Gates Open
Nonadiabatic holonomic quantum computation (NHQC) has been developed to shorten the construction times of geometric quantum gates. However, previous NHQC gates require the driving Hamiltonian to satisfy a set of rather restrictive conditio…
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Spin-controlled wavefront shaping with plasmonic chiral geometric metasurfaces Open
Metasurfaces, as a two-dimensional (2D) version of metamaterials, have drawn considerable attention for their revolutionary capability in manipulating the amplitude, phase, and polarization of light. As one of the most important types of m…
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Recent progress in Pancharatnam–Berry phase optical elements and the applications for virtual/augmented realities Open
In this review paper,we report recent progress on Pancharatnam-Berry (PB) phase optical elements, such as lens, grating, and deflector. PB lenses exhibit a fast switching time between two or more focal lengths with large diopter change and…
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Holonomic Quantum Control by Coherent Optical Excitation in Diamond Open
Although geometric phases in quantum evolution are historically overlooked, their active control now stimulates strategies for constructing robust quantum technologies. Here, we demonstrate arbitrary single-qubit holonomic gates from a sin…
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Photonic spin Hall effect in metasurfaces: a brief review Open
The photonic spin Hall effect (SHE) originates from the interplay between the photon-spin (polarization) and the trajectory (extrinsic orbital angular momentum) of light, i.e. the spin-orbit interaction. Metasurfaces, metamaterials with a …
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Two-dimensional Stiefel-Whitney insulators in liganded Xenes Open
Two-dimensional (2D) Stiefel-Whitney insulator (SWI), which is characterized by the second Stiefel-Whitney class, is a class of topological phases with zero Berry curvature. As an intriguing topological state, it has been well studied in t…
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Gyrotropic effects in trigonal tellurium studied from first principles Open
We present a combined ab initio study of several gyrotropic effects in\np-doped trigonal tellurium (effects that reverse direction with the handedness\nof the spiral chains in the atomic structure). The key ingredients in our study\nare th…
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Strongly Enhanced Berry Dipole at Topological Phase Transitions in BiTeI Open
Transitions between topologically distinct electronic states have been predicted in different classes of materials and observed in some. A major goal is the identification of measurable properties that directly expose the topological natur…
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Magnetotransport phenomena related to the chiral anomaly in Weyl semimetals Open
We present a theory of magnetotransport phenomena related to the chiral\nanomaly in Weyl semimetals. We show that conductivity, thermal conductivity,\nthermoelectric and the sound absorption coefficients exhibit strong and\nanisotropic mag…