Quantum skyrmions are topological structures that have garnered significant interest due to their demonstrated robustness and versatility across diverse optical platforms. However, existing approaches for their generation are limited to producing pre-determined two dimensional qubit states with a single topology. Here we create multi-dimensional topological states by introducing a non-local interaction between high-dimensional photonic entanglement and a metasurface, where the topological transformation induced by the metasurface is made non-deterministic by the probabilistic nature of the interfacing entangled state. Within this framework, we demonstrate that individual quantum states can host multiple co-existing topologies that are only revealed upon measurement, allowing for their parallel transport within distinct spatial mode channels. We confirm this by revealing the rich topological landscape within our modified Hilbert space while controlling the desired output topology by orbital angular momentum (OAM) projections on one of the entangled photons, producing multiple non-local polarization-OAM entangled states characterized by distinct topological classes, all from a single metasurface device. Our results reveal new capability when structured high-dimensional entanglement is interfaced with structured matter capable of coupling photonic degrees of freedom, establishing a new pathway for the compact generation of complex quantum states.
Quantum skyrmions are topological structures that have garnered significant interest due to their demonstrated robustness and versatility across diverse optical platforms. However, existing approaches for their generation are limited to producing pre-determined two dimensional qubit states with a single topology. Here we create multi-dimensional topological states by introducing a non-local interaction between high-dimensional photonic entanglement and a metasurface, where the topological transformation induced by the metasurface is made non-deterministic by the probabilistic nature of the interfacing entangled state. Within this framework, we demonstrate that individual quantum states can host multiple co-existing topologies that are only revealed upon measurement, allowing for their parallel transport within distinct spatial mode channels. We confirm this by revealing the rich topological landscape within our modified Hilbert space while controlling the desired output topology by orbital angular momentum (OAM) projections on one of the entangled photons, producing multiple non-local polarization-OAM entangled states characterized by distinct topological classes, all from a single metasurface device. Our results reveal new capability when structured high-dimensional entanglement is interfaced with structured matter capable of coupling photonic degrees of freedom, establishing a new pathway for the compact generation of complex quantum states.
Quantum optical skyrmions, as topologically robust quantum information carriers, hold transformative potential for resilient high-dimensional quantum information networks. However, their practical exploitation was still restricted to a single quantum channel, which precludes the multiplexing essential for practical high-capacity quantum networks. Here, we utilize a metasurface to achieve multi-channel quantum state distribution of the polarization-entangled photon pairs, inducing a two-photon bunching effect in both the spin and spatial dimensions with compact flat optics. At the spatial bunching port, controlled manipulation of the spin-orbit interaction enables the generation of a tunable single-photon skyrmion pair. In contrast to any prior skyrmion generation, the single-photon skyrmions are mediated and topologically controlled by quantum measurement in multiple channels. Concurrently, during the amplitude and phase modulation process, both the skyrmion localization and the texture helicity can be precisely customized. The proposed tunable single-photon skyromions offer multidimensional controllability and topological stability provide a viable path toward noise-resilient high-dimensional quantum information processing.
Skyrmions, topologically stable field configurations, have recently emerged in classical optics as structured light for high-density data applications. Achieving controllable on-chip generation of single-photon skyrmions, while being highly desirable for quantum information technologies, remains challenging due to the nanoscale confinement of quantum emitters (QEs). Here we demonstrate a metasurface-integrated quantum emitter (metaQE) platform enabling room-temperature on-chip generation of single-photon skyrmions. Near-field coupling between QEs and propitiously designed surface arrays of meta-atoms mediates spin-orbit interaction, transforming nanoscale-localized dipole emission into free-propagating topologically structured photonic modes. By exploiting this approach for structuring quantum emission from different color centers in nanodiamonds, we realize diverse skyrmionic states, including high-order anti-skyrmions and skyrmionium, and thereby demonstrate its universality across QEs. Our work establishes a unified framework for on-chip structured quantum light sources, offering versatile control of high-dimensional topological states, such as skyrmions, and advancing scalable quantum photonic technologies.
Abstract Quantum nanophotonics offers essential tools and technologies for controlling quantum states, while maintaining a miniature form factor and high scalability. Nanophotonic platforms can transfer information from the traditional degrees of freedom (DoFs) of photons, such as spin angular momentum (SAM) and orbital angular momentum (OAM), to the DoFs of the nanophotonic platform—and back, opening new directions for quantum information processing. Recent experiments have utilized, for entanglement the total angular momentum (TAM) of a photon—as a unique DoF of nanophotonic platforms—for demonstrating entanglement in TAM. Here, we unravel the morphing of quantum states of heralded single photons as they couple into and out of the near-field of a nanophotonic system. Through quantum state tomography, we discover that the TAM state of the near-field transforms to a free-space entangled state within a larger Hilbert space of SAM and OAM. Furthermore, we show that this entangled single photon state is in fact a quantum optical Stokes skyrmion with a topological invariant of ±2 ± 2 . The concepts described here bring new ideas and methodologies in developing high-dimensional quantum circuitry on a chip.
Programmable preparation of entangled quantum states is a central requirement for scalable quantum information processing, quantum networking and photonic quantum computing. Topological photonic platforms offer an attractive route towards robust quantum-state generation by encoding information in symmetry- protected optical modes, yet the generated entangled states are typically dictated by the lattice geometry and therefore lack programmability. Here we demonstrate programmable preparation of topological entangled states by inverse engineering the nonlinear optical pump profile of an integrated photonic lattice. Our approach enables deterministic control over both the dimensionality and modal structure of the generated entangled state while preserving its topological character. We experimentally realize silicon photonic topological superlattices in which the nonlinear generation pathway itself becomes programmable via tailored excitations. The superlattices host a multiband manifold of co localized topological interface modes, while coherently controlled inputs synthesize pump superpositions within this protected basis. We showcase this principle by selectively addressing topological biphoton eigenstates, steering correlations to produce a desired target state in a high-dimensional Hilbert space, and inverse-designing pump states that generate targeted Schmidt dimensionalities. Site-resolved two-photon correlation measurements remain reproducible across nominally identical fabricated devices, demonstrating robustness to realistic nanofabrication-induced disorder. Programmable preparation of topological entangled states establishes a pathway towards exploiting topological photonic modes as application-specific quantum resources, enabling tailored input states for high-dimensional quantum communication, quantum networking and photonic quantum computing.
Twisted photons, carrying spin and orbital angular momentum (OAM) in an unbounded-dimensional Hilbert space, has recently sparked significant interest, leading to the discovery of new physics in both classical and quantum optics, furthering our understanding and incubating applications in classical and quantum communication. At the heart of this emerging field is the requirement for versatile, efficient, and robust generation of novel photonic spin-orbit states involving both spin and OAM degrees of freedom (DoFs). However, so far, the generation and manipulation of spin–orbit photons have primarily relied on free-space bulk optics, which, due to their lack of compactness and stability, are unsuitable for large-scale applications. In this work, we address this challenge by dynamically generating and manipulating the photonic spin-orbit states in both integrated microlaser and single photon source systems, leveraging non-Hermitian photonics and chiral quantum optics. We further investigated the generation and control of quantum entanglement between the spin and OAM DoFs of photons via integrated photonic circuits. Moreover, we successfully generated photonic spin-orbit states with intricate Skyrmionic topological structures and demonstrate the robustness of their topological properties during the quantum teleportation process. The integrated spin-orbit control toolbox for various structured photons, combined with the robustness of their topological properties, holds significant potential for developing large-channel capacity, noise-resilient information systems within a unique multidimensional space.
High-dimensional entanglement is of great importance in quantum communications and can be realized by encoding information on multiple degrees of freedom (DoFs) of the photons. Conventionally, the realization of such high-dimensional entanglement involves different combinations of bulky optical elements. In this work, we present the use of a single dielectric metasurface to generate high-dimensional entanglement by modulating multi-DoFs of photons. By sending one of the polarization-entangled photons to interact with the metasurface, we encode path, spin angular momentum, and orbital angular momentum information to the original state. We achieve a four-qubit quantum state in the experiment. To verify it, we experimentally demonstrate the nonlocal correlations between the two photons by recording the correlated images, and we also perform a quantum state tomography measurement. This scheme can be applied to on-chip quantum state manipulation, which is promising in quantum communication with integrated components.