arXiv subjects

Sergey I. Bozhevolnyi

Publications and source records attributed to Sergey I. Bozhevolnyi.

At least 19 recordsLinked to original sources

arXiv2026

Metasurface-on-Lithium-Niobate Architecture for Spin-decoupled Second Harmonic Wavefront Shaping

Nonlinear metasurfaces (NMSs) enable simultaneous generation and manipulation of harmonic light with ultrathin nanophotonic platforms. However, conventional NMSs typically adopt a monolithic single-layer configuration in which frequency conversion, polarization selection and wavefront engineering are intertwined to simultaneously occur within the same nonlinear meta-atoms, making these functionalities intrinsically interdependent and imposing constraints on material choice, structural symmetry, and the available geometric parameter space. Here, we propose and experimentally demonstrate a metasurface-on-lithium-niobate architecture that physically separates harmonic light generation and wavefront manipulation. In this platform, a z-cut thin-film LN layer serves as a spin-selective second-harmonic source through its intrinsic bulk second-order nonlinearity, while an overlaid dielectric metasurface subsequently and independently molds wavefronts of generated harmonic fields. The two-step process, by virtue of harmonic generation being decoupled from wavefront shaping, removes symmetry constraints associated with conventional nonlinear meta-atoms and enables the direct transfer of well-established linear metasurface design strategies to harmonic wavefront engineering. As proof-of-concept demonstrations, we realize spin-decoupled second-harmonic beam steering and spin-multiplexed holography, achieving high-contrast routing of harmonic signals with orthogonal spin states into distinct diffraction channels and high-fidelity reconstruction of independent holographic images. By redirecting the harmonic wavefront control from the meta-atom engineering to the modular system-level design, our approach establishes a versatile route toward integrated nonlinear meta-optics and provides a scalable platform for advanced optical functionalities.

physics.optics↗

arXiv2026

Electro-Optic Active Metasurfaces for High-Speed Photonic Applications

Metasurfaces are artificially engineered ultrathin nanostructured surfaces, capable of flexibly manipulating light-matter interactions on compact platforms, and thereby of great significance for a wide range of applications within modern optics and photonics, including communications, computing, sensing, and quantum technologies. However, the inherently static nature of conventional metasurfaces severely limits their functionalities and thus range of possible applications. Benefiting from integration of the metasurface platform for shaping optical wavefronts with ultrafast electro-optic (EO) materials, active EO metasurfaces have emerged as a frontier research direction targeting advanced photonic devices. This paper systematically reviews the latest progress in this field, featuring a comprehensive comparison of performances and application scenarios of mainstream EO materials such as lithium niobate, barium titanate and organic EO polymers. Modulation mechanisms based on the Pockels and Kerr effects along with the corresponding active metasurface implementations are summarized. Furthermore, improvements in modulation efficiency enabled by advantageously exploiting resonant structural designs and associated phenomena, including Fabry-Perot resonances, Mie resonances, surface plasmon polaritons, quasi-bound states in the continuum, surface lattice resonances, and guided-mode resonances, are presented and summerized in detail. Current challenges related to metasurface design, nanofabrication, performance and heterogeneous integration are also discussed. Finally, future research directions are outlined, highlighting interdisciplinary developments, novel material engineering, and AI-assisted design as key pathways to enable practical use of active EO metasurfaces in modern optics and photonics, including quantum information technologies.

physics.optics↗

arXiv2026

Integrated nanophotonic platform for on-chip quantum emitter interactions and entanglement

Entanglement between solid-state quantum emitters (QEs) is a key resource for photonic quantum technologies. Achieving such entanglement requires strong and controllable long-range interactions between QEs. However, engineering such coupling remains challenging, particularly for on-chip distant solid-state QEs. Here, we introduce a forward-designed platform that enables ultracompact nanophotonic architectures to mediate enhanced long-range QE-QE interactions via engineered surface plasmon polariton interference. Using this strategy, we realize two distinct configurations: a phase-conjugated elliptic design for energy funneling, and a co-radiating hyperbolic design for its suppression. We experimentally demonstrate large enhancement and suppression of energy transfer rates compared to bare substrates. Furthermore, we predict transient entanglement between spatially separated QEs with concurrence peaking at 0.493, approaching the theoretical bound in the transient regime. Extending to the multi-QE case, we observe enhanced energy funneling and predict QE-QE entanglement in three-QE configurations. These results establish a compact and scalable framework for on-chip entanglement engineering in integrated quantum nanophotonic systems.

cond-mat.mes-hall↗

arXiv2026

Chip-integrated metasurface-enabled single-photon skyrmion sources

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.

physics.optics↗

arXiv2025

Dynamic and Continuous Control of Second-Harmonic Chirality through Lithium Niobate Nonlocal Metasurface

Nonlinear chiral light sources are crucial for emerging applications in chiroptics, including ultrafast spin dynamics and quantum state manipulation. However, achieving precise and dynamic control over nonlinear optical chirality with natural materials and metasurfaces, particularly those based on non-centrosymmetric materials such as lithium niobate (LN), is hindered by the complex tensorial nature of the second-order nonlinear susceptibility. Here, we demonstrate a nonlinear nonlocal metasurface, comprising plasmonic nanoantennas atop an x-cut LN thin film, that enables dynamic and continuous control of second-harmonic (SH) chirality. By leveraging two spectrally detuned resonances arising from the excitation of orthogonally propagating guided modes, enabled by lattice anisotropy and LN birefringence, we achieve full-range tuning of SH chirality, from right- to left-handed circular polarization, simply by rotating the polarization of a linearly polarized pump. The SH chirality, quantified by the Stokes parameter S3, is thereby continuously tuned from 0.991 to -0.993 in simulations and from 0.920 to -0.815 in experiments, while maintaining consistently enhanced SH intensity across the entire tuning range. Our approach opens new avenues for developing compact and tunable chiral sources, with potential applications in integrated nonlinear photonics and adaptable quantum technologies.

physics.optics↗

arXiv2025

Integrated angstrom-tunable polarization-resolved solid-state photon sources

The development of high-quality solid-state photon sources is essential to nano optics, quantum photonics, and related fields. A key objective of this research area is to develop tunable photon sources that not only enhance the performance but also offer dynamic functionalities. However, the realization of compact and robust photon sources with precise and wide range tunability remains a long-standing challenge. Moreover, the lack of an effective approach to integrate nanoscale photon sources with dynamic systems has hindered tunability beyond mere spectral adjustments, such as simultaneous polarization control. Here we propose a platform based on quantum emitter (QE) embedded metasurfaces (QEMS) integrated with a microelectromechanical system (MEMS)-positioned microcavity, enabling on-chip multi-degree control of solid-state photon sources. Taking advantages of MEMS-QEMS, we show that typically broadband room-temperature emission from nanodiamonds containing nitrogen-vacancy centres can be narrowed to 3.7 nm and dynamically tuned with angstrom resolution. Furthermore, we design a wavelength-polarization-multiplexed QEMS and demonstrate polarization-resolved control of the MEMS-QEMS emission in a wide wavelength range (650 nm to 700 nm) along with polarization switching at sub-millisecond timescales. We believe that the proposed MEMS-QEMS platform can be adapted for most existing QEs, significantly expanding their room-temperature capabilities and thereby enhancing their potential for advanced photonic applications.

physics.optics↗

arXiv2025

2D semiconductors as integrated light sources for plasmonic waveguides

2D materials are compatible with many material platforms as they adhere to other materials strictly by van der Waals interactions. This, together with the variety of band gaps found among transition metal dichalcogenides (TMDCs), makes them uniquely interesting to study for on-chip light sources, as the photonic integrated circuit (PIC) industry is developing into several material platforms depending on the application (gold, silicon, silicon nitride, indium phosphide, etc). 2D materials could thus potentially provide a universal on-chip light source (and detector) scheme for all PIC platforms in the future. Here we show recent results on how exfoliated monolayer TMDC flakes can be integrated with plasmonic slot-waveguides and plasmonic dipole antenna couplers to inject their photoluminescence into plasmonic waveguides as a first step towards future on-chip light sources for such systems.

physics.optics↗

arXiv2025

Roadmap on Nonlocality in Photonic Materials and Metamaterials

Photonic technologies continue to drive the quest for new optical materials with unprecedented responses. A major frontier in this field is the exploration of nonlocal (spatially dispersive) materials, going beyond the local, wavevector-independent assumption traditionally made in optical material modeling. On one end, the growing interest in plasmonic, polaritonic and quantum materials has revealed naturally occurring nonlocalities, emphasizing the need for more accurate models to predict and design their optical responses. This has major implications also for topological, nonreciprocal, and time-varying systems based on these material platforms. Beyond natural materials, artificially structured materials--metamaterials and metasurfaces--can provide even stronger and engineered nonlocal effects, emerging from long-range interactions or multipolar effects. This is a rapidly expanding area in the field of photonic metamaterials, with open frontiers yet to be explored. In the case of metasurfaces, in particular, nonlocality engineering has become a powerful tool for designing strongly wavevector-dependent responses, enabling enhanced wavefront control, spatial compression, multifunctional devices, and wave-based computing. Furthermore, nonlocality and related concepts play a critical role in defining the ultimate limits of what is possible in optics, photonics, and wave physics. This Roadmap aims to survey the most exciting developments in nonlocal photonic materials, highlight new opportunities and open challenges, and chart new pathways that will drive this emerging field forward--toward new scientific discoveries and technological advancements.

cond-mat.mes-hall↗

arXiv2025

2D semiconductors as on-chip light sources for integrated nanophotonics

Incorporating on-chip light sources directly into nanophotonic waveguides generally requires introducing a different material to the chip than that used for guiding the light, a crucial step that requires dealing with several technical challenges, e.g., atomic lattice mismatch in epitaxial growth between substrate and luminescent materials resulting in strain defects that lower performance. Here we demonstrate that van der Waals materials, such as the 2D semiconductor MoSe2, can easily be transferred onto gold plasmonic nanowaveguides using standard dry visco-elastic polymer transfer techniques. We further show that the photoluminescence from MoSe2 can be injected directly into these on-chip waveguides. Our fabrication methods are compatible with large-scale roll-to-roll manufacturing techniques, highlighting a potential cost-effective and scalable hybrid plasmonic and 2D semiconductor platform for integrated nanophotonics.

physics.optics↗

arXiv2025

Quasi-bound states in the continuum in finite waveguide grating couplers

Finite-size effects occurring for quasi-bound states in the continuum (qBIC) formed in symmetric and asymmetric all-dielectric waveguide grating couplers are investigated using numerical simulations for different configuration parameters. We find that the beam size plays a crucial role in the formation of additional qBIC resonances originating in forbidden for plane-wave incidence BIC resonances, whose manifestation is strongly influenced by the beam divergence. Another parameter is the strength of Bragg reflection, determining the spatial extension of a distributed Bragg resonator (DBR): in configurations with strong Bragg reflection, the excited and Bragg reflected counterpropagating waveguide modes are confined within the footprint of the incident beam. Conversely, the DBR formed in configurations with weak Bragg reflection extends well beyond the incident beam footprint, resulting in high sensitivity of the system response to the grating width and incident beam position. We believe that our findings provide valuable insights for optimizing photonic devices that leverage qBIC resonances in finite-sized structures under realistic excitation conditions.

physics.optics↗

arXiv2025

On-Chip Emitter-Coupled Meta-Optics for Versatile Photon Sources

Controlling the spontaneous emission of nanoscale quantum emitters (QEs) is crucial for developing advanced photon sources required in many areas of modern nanophotonics, including quantum information technologies. Conventional approaches to shaping photon emission are based on using bulky configurations, while approaches recently developed in quantum metaphotonics suffer from limited capabilities in achieving desired polarization states and directionality, failing to provide on-demand photon sources tailored precisely to technological needs. Here, we propose a universal approach to designing versatile photon sources using on-chip QE-coupled meta-optics that enable direct transformations of QE-excited surface plasmon polaritons into spatially propagating photon streams with arbitrary polarization states, directionality, and amplitudes via both resonance and geometric phases supplied by meta-atoms. Leveraging this platform, we experimentally demonstrate the independent engineering of polarization states, directionality, and relative amplitudes of photon emission in single and multiple radiation channels. The developed universal approach represents a major step towards the realization of versatile quantum sources, highlighting the potential of integrated photon sources with superior properties for both classical and quantum information technologies.

physics.optics↗

arXiv2025

Metasurface Polarimeter for Structural Imaging and Tissue Diagnostics

Histopathology, the study and diagnosis of disease through analysis of tissue samples, is an indispensable part of modern medicine. However, the practice is time consuming and labor intensive, compelling efforts to improve the process and develop new approaches. One perspective technique involves mapping changes in the polarization state of light scattered by the tissue, but the conventional implementation requires bulky polarization optics and is slow. We report the design, fabrication and characterization of a compact metasurface polarimeter operating at 640 nm enabling simultaneous determination of Stokes parameters and degree of polarization with $\pm$2% accuracy. To validate its use for histopathology we map polarization state changes in a tissue phantom mimicking a biopsy with a cancerous inclusion, comparing it to a commercial polarimeter. The results indicate a great potential and suggest several improvements with which we believe metasurface polarimeter based devices will be ready for practical histopathology application in clinical environment.

physics.optics↗

arXiv2024

Highly efficient, tunable, electro-optic metasurfaces based on quasi-bound states in the continuum

Ultrafast and highly efficient dynamic optical metasurfaces enabling truly spatiotemporal control over optical radiation are poised to revolutionize modern optics and photonics, but their practical realization remains elusive. In this work, we demonstrate highly efficient electro-optic metasurfaces based on quasi-bound states in the continuum (qBIC) operating in reflection that are amenable for ultrafast operation and thereby spatiotemporal control over reflected optical fields. The material configuration consists of a lithium niobate thin film sandwiched between an optically thick gold back-reflector and a grating of gold nanoridges also functioning as control electrodes. Metasurfaces for optical free-space intensity modulation are designed by utilizing the electro-optic Pockels effect in combination with an ultra-narrow qBIC resonance, whose wavelength can be finely tuned by varying the angle of light incidence. The fabricated electro-optic metasurfaces operate at telecom wavelengths with the modulation depth reaching 95 % (modulating thereby 35 % of the total incident power) for a bias voltage of +/-30 V within the electrical bandwidth of 125 MHz. Leveraging the highly angle-dependent qBIC resonance realized, we demonstrate electrically tunable phase contrast imaging using the fabricated metasurface. Moreover, given the potential bandwidth of 39 GHz estimated for the metasurface pixel size of 22 $μ$m, the demonstrated electro-optic metasurfaces promise successful realization of unique optical functions, such as harmonic beam steering and spatiotemporal shaping as well as nonreciprocal operation.

physics.optics↗

arXiv2023

Inducing room-temperature valley polarization of excitonic emission in transition metal dichalcogenide monolayers

The lowest energy states in transition metal dichalcogenide (TMD) monolayers follow valley selection rules, which have attracted vast interest due to the possibility of encoding and processing of quantum information. However, these quantum states are strongly affected by the temperature-dependent intervalley scattering causing complete valley depolarization, which is hampering any practical applications of TMD monolayers at room temperature. Therefore, for achieving clear and robust valley polarization in TMD monolayers one needs to suppress parasitic depolarization processes, which is the central challenge in the growing field of valleytronics. Here, in electron-doping experiments on TMD monolayers, we demonstrate that strong doping levels beyond $10^{13}$~cm$^{-2}$ can induce 61\% and 37\% valley contrast at room temperature in tungsten diselenide and molybdenum diselenide monolayers, respectively. Our results indicate that charged excitons in TMD monolayers can be utilized as quantum units in designing of practical valleytronic devices operating at 300 K.

cond-mat.mes-hall↗

arXiv2023

Ultracompact single-photon sources of linearly polarized vortex beams

Ultracompact chip-integrated single-photon sources of collimated beams with polarizationencoded states are crucial for integrated quantum technologies. However, most of currently available single-photon sources rely on external bulky optical components to shape the polarization and phase front of emitted photon beams. Efficient integration of quantum emitters with beam shaping and polarization encoding functionalities remains so far elusive. Here, we present ultracompact single-photon sources of linearly polarized vortex beams based on chip-integrated quantum emitter-coupled metasurfaces, which are meticulously designed by fully exploiting the potential of nanobrick arrayed metasurfaces. We first demonstrate on-chip single-photon generation of high-purity linearly polarized vortex beams with prescribed topological charges of -1, 0, and +1. We further realize multiplexing of single-photon emission channels with orthogonal linear polarizations carrying different topological charges and demonstrate their entanglement. Our work illustrates the potential and feasibility of ultracompact quantum emitter-coupled metasurfaces as a new quantum optics platform for realizing chip-integrated high-dimensional single-photon sources.

physics.optics↗

arXiv2023

Single-photon circularly polarized single-mode vortex beams

Generation of single photons carrying spin and orbital angular momenta (SAM and OAM) opens enticing perspectives for exploiting multiple degrees of freedom for high-dimensional quantum systems. However, on-chip generation of single photons encoded with single-mode SAM-OAM states has been a major challenge. Here, by utilizing carefully designed anisotropic nanodimers fabricated atop a substrate, supporting surface plasmon polariton (SPP) propagation, and accurately positioned around a quantum emitter (QE), we enable nonradiative QE-SPP coupling and the SPP outcoupling into free-space propagating radiation featuring the designed SAM and OAM. We demonstrate on-chip room-temperature generation of well-collimated (divergence < 7.5 degrees) circularly polarized (chirality > 0.97) single-mode vortex beams with different topological charges (l = 0, 1, and 2) and high single-photon purity, g(0) < 0.15. The developed approach can straightforwardly be extended to produce multiple, differently polarized, single-mode single-photon radiation channels, and enable thereby realization of high-dimensional quantum sources for advanced quantum photonic technologies.

physics.optics↗

arXiv2023

Scattering holography designed metasurfaces for channeling single-photon emission

Channelling single-photon emission in multiple well-defined directions and simultaneously controlling its polarization characteristics is highly desirable for numerous quantum technology applications. We show that this can be achieved by using quantum emitters (QEs) nonradiatively coupled to surface plasmon polaritons (SPPs), which are scattered into outgoing free-propagating waves by appropriately designed metasurfaces. The QE-coupled metasurface design is based on the scattering holography approach with radially diverging SPPs as reference waves. Using holographic metasurfaces fabricated around nanodiamonds with single Ge vacancy centers, we experimentally demonstrate on-chip integrated efficient generation of two well-collimated single-photon beams propagating along different 15-degree off-normal directions with orthogonal linear polarizations.

physics.optics↗

arXiv2023

Sub-to-super-Poissonian photon statistics in cathodoluminescence of color center ensembles in isolated diamond crystals

Impurity-vacancy centers in diamond offer a new class of robust photon sources with versatile quantum properties. While individual color centers commonly act as single-photon sources, their ensembles have been theoretically predicted to have tunable photon-emission statistics. Importantly, the particular type of excitation affects the emission properties of a color center ensemble within a diamond crystal. While optical excitation favors non-synchronized excitation of color centers within an ensemble, electron-beam excitation can synchronize the emitters and thereby provides a control of the second-order correlation function $g_2(0)$. In this letter, we demonstrate experimentally that the photon stream from an ensemble of color centers can exhibit $g_2(0)$ both above and below unity. Such a photon source based on an ensemble of few color centers in a diamond crystal provides a highly tunable platform for informational technologies operating at room temperature.

cond-mat.mes-hall↗