Entanglement-based quantum science exploits subtle properties of quantum mechanics into applications such as quantum computing, sensing, and metrology. The emerging route for quantum computing applications, which calls for ultracompact, integrated, and scalable architecture, aims at on-chip entangled qubits. In this context, quantum entanglement among atomic qubits was achieved via cold-controlled collisions which are only significant at subwavelength separations. However, as other manifolds of quantum state engineering require single-site addressability and controlled manipulation of the individual qubit using diffraction-limited optics, entanglement of qubits separated by macroscopic distances at the chip level is still an outstanding challenge. Here, we report a novel platform for on-chip quantum state engineering by harnessing the extraordinary light-molding capabilities of metasurfaces. We theoretically demonstrate quantum entanglement between two qubits trapped on a chip and separated by macroscopic distances, by engineering their coherent and dissipative interactions via the metasurface. Spatially scalable interaction channels offered by the metasurface enable robust generation of entanglement, with large values of concurrence and remarkable revival from sudden death. The metasurface route to quantum state engineering opens a new paradigm for on-chip quantum science and technologies.
Entanglement-based quantum science exploits subtle properties of quantum mechanics into applications such as quantum computing, sensing, and metrology. The emerging route for quantum computing applications, which calls for ultracompact, integrated, and scalable architecture, aims at on-chip entangled qubits. In this context, quantum entanglement among atomic qubits was achieved via cold-controlled collisions which are only significant at subwavelength separations. However, as other manifolds of quantum state engineering require single-site addressability and controlled manipulation of the individual qubit using diffraction-limited optics, entanglement of qubits separated by macroscopic distances at the chip level is still an outstanding challenge. Here, we report a novel platform for on-chip quantum state engineering by harnessing the extraordinary light-molding capabilities of metasurfaces. We theoretically demonstrate quantum entanglement between two qubits trapped on a chip and separated by macroscopic distances, by engineering their coherent and dissipative interactions via the metasurface. Spatially scalable interaction channels offered by the metasurface enable robust generation of entanglement, with large values of concurrence and remarkable revival from sudden death. The metasurface route to quantum state engineering opens a new paradigm for on-chip quantum science and technologies.
The convergence of metamaterials and quantum optics heralds a transformative era in photonic technologies, poised to revolutionize applications ranging from information processing and imaging to sensing and beyond. This review explores the synergistic integration of metasurfaces—engineered sub-wavelength planar structures—and quantum optics, which exploits quantum mechanical principles to manipulate light at the most granular level. We outline the design principles, fabrication processes, and computational challenges involved in creating quantum metasurfaces, discussing both forward and inverse design approaches. Advances in nanofabrication and intelligent optimization techniques, such as machine learning and topology optimization, have enabled the development of metasurfaces with unparalleled control over electromagnetic waves. We examine recent progress in using quantum metasurfaces for single-photon and multi-photon generation, quantum imaging, and quantum sensing, showcasing how these innovations achieve unprecedented precision and novel functionalities. Additionally, we highlight the integration of metasurfaces into quantum light manipulation, emphasizing their role in enhancing wavefront shaping and entanglement control. By providing a comprehensive survey of current advancements and future research directions, this review highlights the vast potential of metasurfaces and quantum optics at the crossroads, setting the stage for next-generation technological innovations that will define the forthcoming decade.
Recent progress in meta-optics, particularly the development of metasurfaces, has enabled compact, tunable, and integrable control over the amplitude, phase, polarization, and wavefront of light, thereby allowing a paradigm shift in traditional optical science and engineering. In parallel, the ability to generate and precisely manipulate nonclassical light is central to quantum optics, enabling key functionalities in secure quantum communication, precision measurement, and scalable quantum computation. This review aims to bridge these two rapidly advancing fields by presenting recent progress in the application of structured materials to the manipulation of quantum states of light. We begin by introducing the concept of singular optics, followed by a discussion of various families of spatially and temporally structured beams that form the foundation for many of the phenomena explored in quantum photonics. Next, we revisit the theoretical framework of quantum optics, including the formalism of photon quantization and the principles governing quantum frequency conversion. We then examine how metasurfaces can be engineered to enable highly efficient nonlinear quantum processes, including both up-conversion and down-conversion, thereby offering new approaches for generating and controlling complex quantum states. Furthermore, we discuss the crucial role of structured materials in shaping the properties of quantum light and in applications such as quantum ghost imaging. The review concludes by identifying emerging directions for integrating meta-optical platforms with quantum systems, highlighting their potential for scalable manipulation of nonclassical light at the nanoscale.
Trapped neutral atoms are one of the leading platforms for quantum information technologies, in particular for quantum computing, but scaling them to array sizes needed for utility-scale quantum computing is a major engineering challenge. Here we review optical metasurfaces as an enabling technology that provides fine control over the phase, amplitude, and polarization of light, with pixel counts far exceeding what is available with spatial light modulators (SLMs) and other active devices. The large pixel counts have recently led to demonstrations of arrays of optical tweezers with hundreds of thousands of sites and arrays of optical bottle-beams with complex three-dimensional trapping profiles. The flexibility and scalability of optical metasurfaces provides a route towards miniaturized, integrated, and highly scalable atomic experiments and instruments.
Multipartite entanglements are essential resources for proceeding tasks in quantum information science and technology. However, generating and verifying them present significant challenges, such as the stringent requirements for manipulations and the need for a huge number of building-blocks as the systems scale up. Here, we propose and experimentally demonstrate the heralded multipartite entanglements on a three-dimensional photonic chip. Integrated photonics provide a physically scalable way to achieve an extensive and adjustable architecture. Through sophisticated Hamiltonian engineering, we are able to control the coherent evolution of shared single photon in the multiple spatial modes, dynamically tuning the induced high-order W-states of different orders in a single photonic chip. Using an effective witness, we successfully observe and verify 61-partite quantum entanglements in a 121-site photonic lattice. Our results, together with the single-site-addressable platform, offer new insights into the accessible size of quantum entanglements and may facilitate the developments of large-scale quantum information processing applications.
The pursuit of scalable and robust quantum computing necessitates innovative approaches to overcome the inherent challenges of qubit connectivity, decoherence, and susceptibility to noise and crosstalk. Conventional monochromatic qubit coupling architectures, constrained by nearest-neighbor interactions and limited algorithmic flexibility, exacerbate these issues, hindering the realization of practical large-scale quantum processors. In this work, we introduce a paradigm leveraging a space-time-modulated cryogenic-compatible Josephson metasurface to enable polychromatic qubit coupling. This metasurface facilitates frequency-selective interactions, transforming nearest-neighbor connectivity into all-to-all qubit interactions, while significantly enhancing coherence, noise robustness, and entanglement fidelity. Our proposed approach capitalizes on the unique capabilities of space-time-modulated Josephson metasurfaces, including dynamic four-dimensional wave manipulation, nonreciprocal state transmission, and state-frequency conversion, to mediate multi-frequency qubit interactions. By isolating qubit couplings into distinct spectral channels, the cryogenic-compatible metasurface mitigates crosstalk and environmental decoherence, extending coherence times and preserving quantum state fidelity. Full-wave simulations and quantum performance analyses demonstrate a significant enhancement in the operational efficiency of a superconducting qubit array, showcasing improved connectivity, robustness, and entanglement stability. This study establishes the potential of space-time-modulated cryogenic-compatible Josephson metasurfaces as a transformative platform for next-generation quantum computing, addressing critical bottlenecks and paving the way for scalable, high-performance quantum processors.