arXiv subjects

Yijie Shen

Publications and source records attributed to Yijie Shen.

At least 55 records · Page 3Linked to original sources

arXiv2025

Topological robustness of classical and quantum optical skyrmions in atmospheric turbulence

The degradation of classical and quantum structured light induced by complex media constitutes a critical barrier to its practical implementation in a range of applications, from communication and energy transport to imaging and sensing. Atmospheric turbulence is an exemplary case due to its complex phase structure and dynamic variations, driving the need to find invariances in light. Here we construct classical and quantum optical skyrmions and pass them through experimentally simulated atmospheric turbulence, revealing the embedded topological resilience of their structure. In the quantum realm, we show that while skyrmions undergo diminished entanglement, their topological characteristics maintain stable. This is paralleled classically, where the vectorial structure is scrambled by the medium yet the skyrmion remains stable by virtue of its intrinsic topological protection mechanism. Our experimental results are supported by rigorous analytical and numerical modelling, validating that the quantum-classical equivalence of the topological behaviour is due to the non-separability of the states and one-sided nature of the channel. Our work blurs the classical-quantum divide in the context of topology and opens a new path to information resilience in noisy channels, such as terrestrial and satellite-to-ground communication networks.

physics.optics↗

arXiv2025

Free-form conformal metasurfaces robustly generating topological skyrmions

Skyrmions are topologically stable vector textures as potential information carriers for high-density data storage and communications, especially boosted by the recently emerging meta-generators of skyrmions in electromagnetic fields. However, these implementations always rely on planar, rigid designs with stringent fabrication requirements. Here, we propose the free-form conformal metasurface generating skyrmions towards future wearable and flexible devises for topological resilience light fields. Furthermore, we experimentally tested the outstanding topological robustness of the skyrmion number under different disorder degrees on the metasurface. This work promotes the development of flexible compact skyrmion-based communication devices and demonstrates their potential to improve the quality of space information transmission.

physics.optics↗

arXiv2025

Electric-Magnetic-Switchable Free-Space Skyrmions in Toroidal Light Pulses via a Nonlinear Metasurface

Recent advances reveal that light propagation in free space supports many exotic topological textures, such as skyrmions. Their unique space-time topologies make them promising candidates as next-generation robust information carriers. Hence, the ability of switching different texture modes is highly demanded to serve as a manner of data transfer. However, previous studies focus on generation of one specific mode, lacking integrated devices with externally variable and stable mode generation capability. Here, we experimentally demonstrate the first realization of switchable skyrmions between electric and magnetic modes in toroidal light pulses using a nonlinear metasurface platform in terms of broadband terahertz generation driven by vectorial pulse. The spatial and temporal evolutions of them are also clearly observed. Our work establishes a new paradigm for manipulating and switching topologically structured light.

physics.optics↗

arXiv2025

Meron Spin Textures in Momentum Space Spawning from Bound States in the Continuum

Topological spin textures, such as merons and skyrmions, have shown significance in both fundamental science and practical applications across diverse physical systems. The optical skyrmionic textures in real space have been extensively explored, but which in momentum space are still rarely studied. Here, we report the experimental generation of momentum-space meron spin textures via bound states in the continuum (BICs) in photonic crystal slabs. We show that under circularly polarized illumination, the momentum-space vortex topology of BICs can transform light with meron spin textures in momentum space. These merons exhibit polarity-switchable configurations controlled by incident light polarization. We theoretically and experimentally verify the generation of momentum-space merons and demonstrate their operational flexibility across a broad spectral range. Our results establish a connection between different momentum-space topologies and provide a robust and compact platform for generating topological spin textures.

physics.optics↗

arXiv2025

On-chip photon entanglement-assisted topology loading and transfer

Topological protection offers a robust solution to the challenges of noise and loss in physical systems. By integrating topological physics into optics, loading and encoding quantum states into topological invariants can provide resilience to information systems in the face of environmental disruptions. Here, we demonstrate on-chip loading and entanglement-assisted transfer of photon topology, where the topological structure is coherently encoded in a single-photon spin-textured quantum state, which can be transferred, through entanglement distribution, into a non-local quantum-correlated topology shared between two entangled photons. Throughout the transfer process, the topology remains protected against substantial background noise as well as isotropic and anisotropic disturbances, while quantum correlations persist. Our framework for loading and transferring topology is compatible with quantum teleportation when ancillary photons are introduced, thereby promising the development of distributed quantum systems with inherently secure and protected information channels. This approach serves as a step toward building robust quantum interconnects and advancing distributed quantum information technology mediated by topology.

quant-ph↗

arXiv2025

Tailoring ultra-high-order optical skyrmions

Skyrmions, as quasiparticles with topological spin textures, has recently garnered great attention for both condensed matter and structured wave communities, promising next-generation large-density robust information technologies. However, a big challenge to this end is that the generation of high-order skyrmions is elusive in any physical systems. Here, we propose the method to create and control ultra-high-order skyrmions (skyrmion number up to $400^{th}$) in a structured light system. We also experimentally control the topological state transition between bimeron and skyrmion, arbitrarily tailor the transverse size of an arbitrary-order skyrmionic beam independent of topological number, and ensure the topological stability upon propagation. Our work offers solutions for topologically resilient communication and memory with much enhanced information capacity.

physics.optics↗

arXiv2025

Fully Tunable On-Chip Meta-Generator for Multidimensional Poincaré Sphere mapping

The angular momentum of light can be elegantly mapped onto high-order Poincare spheres, providing a powerful framework for describing structured light beams. Such beams have shown extraordinary potential across diverse applications, including high-capacity optical communications, precision metrology, and quantum information processing. While various methods exist for generating structured light beams, the dynamic synthesis and flexible control of arbitrary vectorial states on diverse, multidimensional Poincare spheres still rely on bulky free-space optical components, posing significant challenges for scalability and integration. To date, a fully tunable solution implemented on a single photonic chip has yet to be realized. Here, we present the first fully tunable on-chip meta-generator capable of dynamically mapping arbitrary scalar, vectorial, and hybrid modes onto the full hierarchy of Poincare spheres, and even extending to a high-dimensional Poincare hypersphere within a four-dimensional Hilbert space. Our device is implemented on an eight-channel space-multiplexed multimode silicon photonic integrated circuit, where densely integrated mode multiplexers, amplitude-phase modulators, and an inverse-designed multimode meta-waveguide together enable compact, precise, and programmable control of structured light. The multimode meta-waveguide directly maps eight on-chip guided modes to orbital angular momentum (OAM), supporting broadband generation of high-purity OAM modes with diverse polarization states and topological charges. By simultaneously engineering amplitude, phase, polarization, and topological charge, we achieve full-field control over OAM mode bases, enabling fully tunable access to arbitrary scalar and vectorial states across more than eight distinct Poincare spheres.

physics.optics↗

arXiv2025

Simultaneous Superoscillations in Space and Time in Nonseparable Light Pulses

A remarkable phenomenon of superoscillations implies that electromagnetic waves can locally oscillate in space or time faster than the fastest spatial and temporal Fourier component of the entire function. This phenomenon allows to focus light into an arbitrary small hotspot enabling superresolution imaging and optical metrology with accuracy far beyond the Abbey-Reileigh diffraction limit. Here we show that, in band-limited supertoroidal light pulses, the temporal and spatial superoscillations can be observed simultaneously at a specific region in space and at a specific interval in time.

physics.optics↗

arXiv2025

Topological optical skyrmion transfer to matter

The ability of structured light to mimic exotic topological skyrmion textures, encountered in high-energy physics, cosmology, magnetic materials, and superfluids has recently received considerable attention. Despite their promise as mechanisms for data encoding and storage, there has been a lack of studies addressing the transfer and storage of the topology of optical skyrmions to matter. Here, we demonstrate a high-fidelity mapping of skyrmion topology from a laser beam onto a gas of cold atoms, where it is detected in its new non-propagating form. Within the spatial overlap of the beam and atom cloud, the skyrmion topological charge is preserved, with a reduction from $Q \simeq 0.91$ to $Q \simeq 0.84$ mainly due to the beam width exceeding the sample size. Our work potentially opens novel avenues for topological photonics state storage and the analysis of more complex structured light topologies.

physics.optics↗

arXiv2025

Poincaré sphere engineering of dynamical ferroelectric topological solitons

Geometric representation lays the basis for understanding and flexible tuning of topological transitions in many physical systems. An example is given by the Poincaré sphere (PS) that provides an intuitive and continuous parameterization of the spin or orbital angular momentum (OAM) light states. Here, we apply this geometric construction to understand and continuously encode dynamical topologies of ferroelectric solitons driven by OAM-tunable light. We show that: (1) PS engineering enables controlled creation of dynamic polar antiskyrmions that are rarely found in ferroelectrics; (2) We link such topological transition to the tuning of the light beam as a ``knob'' from OAM (PS pole) to non-OAM (PS equator) modes; (3) Intermediate OAM-state structured light results in new ferroelectric topologies of temporally hybrid skyrmion-antiskyrmion states. Our study offers new approaches of robust control and flexible tuning of topologies of matter using structured light.

cond-mat.mtrl-sci↗

arXiv2025

Optical Skyrmions of Vortex Darkness

We disclose the existence of a type of optical skyrmion, Gauss-Stokes (GS) skyrmions, that is naturally present in an optical vortex around its phase singularity. Contrary to previous research with optical skyrmions, we neither shape vector beams nor superpose different spatial modes and polarizations. In GS skyrmions, the phase singularity in the transversal field of a single monochromatic beam of uniform polarization (a scalar beam) is concealed by the axial field dictated by Gauss's divergence law, giving rise to a polarization singularity of undefined polarization plane. This singularity is enclosed by a rich skyrmionic polarization texture fulfilling a topological map and covering all the states of transverse-axial polarization. In our experiment, we facilitate the observation of a GS skyrmion with the predicted features using focused fields with enhanced axial component.

physics.optics↗

arXiv2025

Optical skyrmion lattices accelerating in free space

Generation and propagation of optical skyrmions provide a versatile plalform for topologically nontrivial optical informatics and light-matter interactions, but their acceleration along curved trajectories is to be studied. In this study, we experimentally demonstrate the first accelerating skyrmion lattices conveyed by Airy structured light, characterized by topologically stable skyrmion textures with self-acceleration along parabolic trajectories. We show that the skyrmion unit cell can maintain a Skyrme number $|N_\text{sk}|>0.9$ within a propagation range of $\pm1.22\ z_R$ upon parabolic acceleration. Notably, the meron structure remains $|N_\text{sk}|$ stable within $0.5\pm0.02$ over a significantly extended range of $\pm3.06\ z_R$. Our work provides a new potential carrier for topologically robust information distribution, particle sorting and manipulation.

physics.optics↗

arXiv2024

Photonic torons, topological phase transition and tunable spin monopoles

Creation and control of topological complex excitations play crucial roles in both fundamental physics and modern information science. Torons are a sophisticated class of 3D chiral polar topological structures with both skyrmionic quasiparticle textures and monopole point defects, so far only observed in liquid crystal nonpolar models. Here, we experimentally construct torons with the photonic spin of vector structured light and demonstrate the topological phase transitions among diverse topological states: torons, hopfions, skyrmioniums and monopole pairs. We can also continually tune the toron's chirality and the helical spin textures of emerging monopole pairs. The birth of photonic torons and tunable monopoles opens a flexible platform for studying nontrivial light-matter interaction and topological informatics.

physics.optics↗

arXiv2024

Topological Momentum Skyrmions in Mie Scattering Fields

Topological quasiparticles such as skyrmions and merons have recently attracted enormous attentions in the form of diverse optical degrees of freedom. However, these structures have not been explored in the fundamental momentum vectors of optical fields yet. Here, we reveal the universality of forming skyrmion and meron topological textures from the Poynting vector, canonical momentum, and optical spin field, which are generated from multipole Mie scattering fields. Moreover, we analyze the unconditional topological stability of the skyrmionic momentum fields against perturbation and geometric defects. This work reveals the topological properties of multipole scattered field and will spur new phenomena related to optical forces, metamaterial design and unique light-matter interaction.

physics.optics↗

arXiv2024

Spintwistronics: Photonic bilayer topological lattices tuning extreme spin-orbit interactions

Twistronics, the manipulation of Moiré superlattices via the twisting of two layers of two-dimensional (2D) materials to control diverse and nontrivial properties, has recently revolutionized the condensed matter and materials physics. Here, we introduce the principles of twistronics to spin photonics, coining this emerging field spintwistronics. In spintwistronics, instead of 2D materials, the two layers consist of photonic topological spin lattices on a surface plasmonic polariton (SPP) platform. Each 2D SPP wave supports the construction of topological lattices formed by photonic spins with stable skyrmion topology governed by rotational symmetry. By introducing spintwistronics into plasmonics, we demonstrate theoretically and experimentally that two layers of photonic spin lattices can produce Moiré spin superlattices at specific magic angles. These superlattices, modulated periodically by the quantum number of total angular momentum, exhibit novel properties-including new quasiparticle topologies, multiple fractal patterns, extremely slow-light control, and more-that cannot be achieved in conventional plasmonic systems. As a result, they open up multiple degrees of freedom for practical applications in quantum information, optical data storage and chiral light-matter interactions.

physics.optics↗

arXiv2024

Observation of Superoscillation Superlattices

Superoscillation (SO) wavefunctions, that locally oscillate much faster than its fastest Fourier component, in light waves have enhanced optical technologies beyond diffraction limits, but never been controlled into 2D periodic lattices. Here, we report the 2D superoscillation lattices (SOL) with controlled symmetries, where the local wavevector can be 700 times larger than the global maximal wavevector (k0) in a localized region 100 times smaller than the global minimal wavelength (λ0). We also demonstrate the superoscillation superlattices (SOSL) as twisted bilayer Moiré patterns of two SOL, akin to the magic angle tuning in advanced twistronics, we can continually tune the ondemand SO with local maximal wavevector in a range of 450k0 to 700k0 and with λ0/100 toλ0/1000. The twistronic SOSL will advance optical imaging and metrology into extreme higher dimensional superresolution.

physics.optics↗

arXiv2024

Generalized Skyrmions

Skyrmions are important topologically non-trivial fields characteristic of models spanning scales from the microscopic to the cosmological. However, the Skyrmion number can only be defined for fields with specific boundary conditions, limiting its use in broader contexts. Here, we address this issue through a generalized notion of the Skyrmion derived from the De Rham cohomology of compactly supported forms. This allows for the definition of an entirely new $\coprod_{i=1}^\infty \mathbb{Z}^i$-valued topological number that assigns a tuple of integers $(a_1, \ldots, a_k)\in \mathbb{Z}^k$ to a field instead of a single number, with no restrictions to its boundary. The notion of the generalized Skyrmion presented in this paper is completely abstract and can be applied to vector fields in any discipline, not unlike index theory within dynamical systems. To demonstrate the power of our new formalism, we focus on the propagation of optical polarization fields and show that our newly defined generalized Skyrmion number significantly increases the dimension of data that can be stored within the field while also demonstrating strong robustness. Our work represents a fundamental paradigm shift away from the study of fields with natural topological character to engineered fields that can be artificially embedded with topological structures.

physics.optics↗

arXiv2024

Double-Helix Singularity and Vortex-Antivortex Annihilation in Space-Time Helical Pulses

Topological structures reveal the hidden secrets and beauty in nature, such as the double helix in DNA, whilst, the manipula-tion of which in physical fields, especially in ultrafast struc-tured light, draw booming attention. Here we introduce a new family of spatiotemporal light fields, i.e. helical pulses, carry-ing sophisticated double-helix singularities in its electromag-netic topological structures. The helical pulses were solved from Maxwell's equation as chiral extensions of toroidal light pulses but with controlled angular momentum dependence. We unveil that the double helix singularities can maintain their topological invariance during propagation and the field exhibits paired generation and annihilation of vortices and antivortices in ultrafast space-time, so as to be potential information carriers beating previous conventional vortex structured light.

physics.optics↗