arXiv subjects

Yuri Kivshar

Publications and source records attributed to Yuri Kivshar.

At least 19 recordsLinked to original sources

arXiv2026

Enhanced chiral response of hybrid photonic structures empowered by Mie resonances

Chiroptical response provides a powerful route to control light-matter interactions through light handedness, with crucial importance in polarization control, chiral sensing, and nonlinear photonics. Hybrid structures may offer a novel route to engineer such responses by coupling plasmonic field localization with dielectric Mie resonances within a single nanostructure. However, in chiral metasurfaces, hybridization has largely been treated as a means of resonance enhancement, while its role in actively reshaping and reversing intrinsic plasmonic chirality remains largely unexplored. Here, we demonstrate a hybrid metasurface in which a dielectric Mie resonance mediates enhanced chiral response of plasmonic building blocks. By coupling a Si nanocylinder to trapezoidal Au nanobars, a weak and mode-selective plasmonic chiral seed is reorganised into two opposite-handed hybrid resonances, producing near-unity circular dichroism with spectral sign flipping. Extending this mechanism to nonlinear regime, the same hybrid-mode selectivity produces strongly nonlinear chiral emission and near-unity third-harmonic generation circular dichroism of either sign. We believe these results establish plasmonic-Mie hybridization as a novel mechanism for engineering high-purity, sign-switchable linear and nonlinear chirality in compact metadevices.

physics.optics↗

arXiv2026

Optical chirality of membrane metasurfaces with broken in-plane symmetry

We study chiroptical properties of single-layer dielectric membrane metasurfaces with broken in-plane symmetry. In sharp contrast to a common belief that chiral optical phenomena require symmetry breaking in the vertical direction, we show that flat single-layer metasurfaces are capable of strong specific chiral effects. Although the single-layer geometry forbids conventional co-polarized circular dichroism, strong resonant conversion circular dichroism appears to be possible in particular wavelength ranges determined by the spectra of photonic eigenmodes. We explore its origin starting with a $C_4$ rotation-symmetric and in-plane mirror-symmetric membrane metasurface and applying to it various in-plane perturbations. Simultaneously breaking of the in-plane mirror symmetry and lifting the rotation symmetry unlocks resonantly enhanced circular conversion dichroism. We derive selection rules for this effect and trace its origin to eigenmode interference and intercoupling using chiral coupled-mode theory.

physics.optics↗

arXiv2026

Fostering cultural change in research through innovative knowledge sharing, evaluation, and community engagement strategies

Bringing together researchers, funders, industry partners, and publishers from 14 countries across 5 continents, we advance the debate around open-science, assessment and learning. We introduce an integrative "open knowledge system" framework linking knowledge production, validation, assessment, and reuse into one ecosystem view, and translate it into actionable recommendations for each stakeholder. Shifting focus to modular, machine-readable knowledge objects, these recommendations are intended to help diagnose misaligned incentives and guide reforms that properly value all scientific contributions.

cs.SI↗

arXiv2026

Hopping of nanoparticles in optical tweezers governed by Mie resonances

Optical tweezers have become a standard tool for manipulating microscale and nanoscale particles and probing their local environments. However, complex particle dynamics under optical forces typically require structured light fields, multi-beam traps, or engineered environments. Here we achieve complex particle dynamics in a single Gaussian-beam optical tweezer. The effect originates from higher-order Mie resonances supported by wavelength-scale particles. In our optical tweezer, small particles in the regime of Rayleigh scattering or the lowest-order dipole-type Mie modes remain confined at the beam center. By contrast, particles within the range of sizes corresponding to quadrupole-type Mie modes exhibit more complex behavior. In a linearly polarized Gaussian beam, these particles are trapped in a potential with two off-axis equilibria. We observe thermally driven hopping between these equilibria, with the hopping frequency controlled by the laser power. In a circularly polarized Gaussian beam, the particles are confined to a stable orbit and exhibit circular motion driven by the spin (circular-polarization) degree of freedom of the beam, with angular velocity dependent on the laser power. These results reveal higher-order Mie resonances as an intrinsic mechanism behind complex optical forces. This establishes Mie-resonant nanophotonics as a flexible platform for inducing and controlling complex motion in optical tweezers for nanoparticle manipulation as well as sensing of local environments.

physics.optics↗

arXiv2026

Optical Supertorque Induced by Mie-Resonant Modes

We introduce the concept of resonant optical torque that allows enhancing substantially a transfer of optical angular momentum (AM) of light to a subwavelength particle. We consider high-index cylindrical dielectric nanoparticles supporting Mie resonances, and explore a transfer of AM and how it is affected by absorption and particle shape. We analyze a simple trapping geometry of standing wave patterns created by opposite helical light waves. We uncover stable rotation of particles in both nodes and anti-nodes, and also study how specific particle properties influence the resonant optical torque. We demonstrate that adjusting particle asymmetry and losses can maximize spinning torque, and we predict "supertorque" originating from the scattering channel mixing. Our study offers a deeper understanding of the physics of resonant optical torque and its importance in manipulating AM transfer in optical systems, with promising implications for various fields and inspiring further research in resonant light-matter interactions.

physics.optics↗

arXiv2026

Engineering Hybrid Resonances in Nanophotonics

Hybridization of resonances is known to overcome inherent limitations of individual systems, enabling advanced functionalities and applications. Here we discuss hybrid plasmonic-Mie resonators that emerged recently as a promising direction in advancing nanophotonic structures by synergistically combining the strong near-field enhancement of plasmonic components with the low-loss, multipolar resonances of dielectric Mie elements. We review the recent progress in the field, encompassing the fundamental physical principles, structural design strategies, material platforms, computational optimization approaches, and representative device implementations. Our discussion starts by evaluating the complementary characteristics of plasmonic and Mie resonances followed by a description of the coupling between these resonances in order to boost light-matter interactions. Afterward, we explore the performance of efficient hybrid resonators for different application areas. Apart from the conventional metal-dielectric systems, we consider the recent class of epsilon-near-zero (ENZ) materials, which can provide unique advantages in terms of field localization, phase engineering, and energy flow management in the vicinity of zero-permittivity conditions, offering more flexibility in designing hybrid nano-optical devices. Lastly, we point out potential research avenues aiming to improve functional and efficient nanophotonic devices, especially those involving emerging topological material systems, such as Sb2Te3, Bi2Te3, Bi2Se3, combining plasmonic amplification, dielectric confinement, and spin-dependent optical behavior.

physics.optics↗

arXiv2026

Mie-tronics supermodes and symmetry breaking in nonlocal metasurfaces

It is usually believed that symmetry breaking in photonic systems leads to weaker optical confinement, such as in the case of metasurfaces when bound states in the continuum are replaced by quasi-bound states with lower quality factors (Q factors). Here we show that symmetry breaking can instead enhance light trapping by strengthening in-plane nonlocal coupling pathways. We consider finite-size arrays of optical resonators supporting Mie resonances (a Mie-tronics platform) and employ diffraction and multiple-scattering analyses. We demonstrate that diffractive bands and Mie-tronics supermodes originate from the same underlying Mie resonances but differ fundamentally in their physical nature. Finite arrays exhibit Q-factor enhancement driven by redistributed radiation channels, and reversing the trends predicted by infinite-lattice theories. We reveal that controlled symmetry breaking opens new electromagnetic coupling channels, enabling polarization conversion in nonlocal metasurfaces. These novel findings establish a unified wave-physics platform linking both scattering and diffraction theories. Also, they outline the design principles for multi-functional metasurfaces that exploit nonlocality for advanced light manipulation, computation, and emission control.

physics.optics↗

arXiv2026

Intrinsic chirality of dielectric metasurfaces unlocked by resonant chiral modes

Controlling optical chirality at the subwavelength scales is essential for many applications of nanophotonic structures in polarization optics, sensing, and nonlinear photonics. Achieving a strong chiroptical response in planar dielectric metasurfaces without intrinsically chiral building blocks (or "meta-atoms") remains challenging. The recent theoretical study [ACS Photonics 12, 6717 (2025)] predicted that bilayer metasurfaces with rotated C$_4$-symmetric apertures can exhibit pronounced chiral response originating from resonant chiral photonic modes realizing maximum chirality under the mode strong coupling. That observation uncovers a novel mechanism of metasurface chirality. Here, we confirm experimentally this novel concept and demonstrate resonantly enhanced circular dichroism in the near-infrared frequency range. We fabricate a free-standing silicon membrane metasurface that is nominally achiral. When out-of-plane symmetry is broken by a thin PMMA layer, it unlocks and activates a strong chiral response. The observed circular dichroism is explained by the properties of chiral photonic modes, and it is governed by interlayer coupling and symmetry breaking, in agreement with theoretical predictions. These results establish bilayer metasurfaces as a simple and versatile platform for engineering strong mode-induced chirality in compact planar photonic metadevices.

physics.optics↗

arXiv2026

Radiation forces and torques in optics and acoustics

The mechanical action of various kinds of waves has been recognized for several centuries. The first tide of scientific interest in wave-induced forces and torques emerged at the turn of the 20th century, with the development of wave theories and the concepts of wave momentum and angular momentum. A second surge occurred in the past several decades, driven by technological breakthroughs: the invention of lasers and the controlled generation of structured wave fields. This resulted in major discoveries, including optical trapping and manipulation of small particles, from atomic to micro sizes, as well as acoustic manipulation of larger particles, including biological cells and samples. Nowadays, radiation forces and torques underpin numerous applications: optical and acoustic tweezers, acoustofluidic sorting of biological cells, optomechanical systems operating in both classical and quantum regimes, solar sails, quantum simulators, volumetric displays, etc. In this review, we present a unifying perspective on optical and acoustic forces and torques acting on various particles, addressing both their theoretical foundations and key applications. Our approach relies on the universal connection between the local energy, momentum, and spin densities of wave fields and the principal forces and torques exerted on small particles. Moreover, we describe important cases of nontrivial (e.g., lateral and pulling) forces and complex (e.g., chiral and anisotropic) particles. We also highlight significant experimental achievements involving optical and acoustic manipulation in structured wave fields. Our aim is to illuminate the common fundamental origins and close interconnections between the mechanical actions of optical and acoustic fields, thereby fostering a deeper understanding and advancing the development of optomechanical and acoustomechanical applications.

physics.optics↗

arXiv2026

Multiresonant Membrane Metasurfaces for Multifunctional Fingerprint Recognition and Real-time Biochemical Tracking

Label-free identification and real-time tracking of biochemical substances became critical for molecular diagnostics and chemical analysis, yet conventional resonant terahertz metasurface sensing relies on a single resonance, limiting spectral selectivity and dynamic capability. Here, we suggest multiresonant membrane metasurfaces and implement them for simultaneous static molecular fingerprint retrieval and dynamic reaction monitoring within a single pixel. We consider a membrane metasurface supporting multiple quasi-bound states in the continuum designed at target frequencies and enabling the tailoring of the field enhancement and frequency-selective interaction with target analytes. As a proof-of-concept, we achieve label-free detection of the dual fingerprint absorption features of pefloxacin at 0.78 THz and 0.99 THz, and real-time tracking of vitamin C oxidation and denaturation under ambient conditions. The kinetic profiles extracted from the THz amplitude evolution show excellent agreement with nonlinear reaction models, demonstrating quantitative biochemical tracking capabilities. Our results establish a versatile and scalable THz photonic platform that unifies static fingerprint identification and dynamic reaction monitoring, paving the way toward integrated on-chip biochemical analytics and multifunctional metasurface sensors.

physics.optics↗

arXiv2026

Nonlinear chiral response governed by meta-atom rotation

Chiral photonics provides powerful routes for controlling the light handedness, yet nonlinear chiral responses are typically associated with intricate three-dimensional systems. Here, we demonstrate that strong nonlinear chirality can emerge and be precisely tuned in planar metasurfaces. We study free-standing membrane metasurfaces composed of periodic lattices of tilted elliptic holes, which preserve out-of-plane mirror symmetry while breaking all in-plane mirror symmetries through the in-plane rotation of the meta-atoms. We demonstrate that optical resonances play a decisive role in governing the nonlinear chiral response, enabling pronounced circular dichroism in third-harmonic generation even when symmetry is broken only in plane. We experimentally reveal strong nonlinear chiral response from the metasurfaces and a striking swapping of nonlinear chiral channels for complementary meta-atom rotation angles. This behaviour arises from the interplay between lattice symmetry and meta-atom orientation, which controls the symmetry of the resonant modes and the resulting nonlinear selection rules. Our results establish meta-atom rotation as a powerful mechanism for engineering nonlinear chiral responses in planar metasurfaces, opening new opportunities for tunable chiral nonlinear metaphotonics devices.

physics.optics↗

arXiv2026

Digital nanophotonic biosensing empowered by silicon Mie voids

Optical biosensors are indispensable in medical and environmental diagnostics, yet existing approaches are fundamentally limited in their sensitivity due to ensemble-averaged measurements. Digital biosensing has emerged as a promising solution for resolving individual binding events, thereby providing signals at very low analyte concentrations down to the single-molecule level. Here, we present a novel concept for digital optical biosensing empowered by dielectric Mie voids, combining nanoparticle-based contrast enhancement and deep learning for ultrasensitive biomarker detection. The resonantly trapped light in the air cavities of the periodic Mie void arrays ensures strong overlap between the near-fields and the single gold nanoparticles that are captured on the surface in the presence of the protein biomarker. Remarkably, this strong interaction creates high-contrast digital signals for the precise counting of single nanoparticles located both within and outside the voids, yielding efficient use of the entire sensor area for high sensitivity. We employ deep-ultraviolet (DUV) lithography for the scalable and low-cost production of Mie voids in silicon wafers and automated image analysis with a convolutional neural network for robust nanoparticle counting. As a proof of our concept, we demonstrate the detection of an important disease biomarker, interleukin-6 (IL-6), from small sample volumes at concentrations as low as 1.84 pg/ml, within the physiological range of healthy individuals. Owing to its scalability, precision, and adaptability, our digital nanophotonic biosensing approach based on silicon Mie voids establishes a versatile route for applications ranging from bioanalytics to health and environmental monitoring.

physics.optics↗

arXiv2026

Observation of Janus Chirality for Coherent Thermal Emission from Metasurfaces

Metasurfaces emerged as a powerful tool for controlling thermal radiation, yet achieving coherent emission with opposite circular handednesses remains a highly challenging problem. Here, we demonstrate experimentally the Janus chiral thermal emission from metasurfaces with opposite circular handednesses on either side of a single device. We employ anisotropic metasurfaces supporting high-Q resonances with photonic flatbands enabling near-unity circular dichroism through in-plane symmetry control. Our experiments confirm the Janus coherent emission, and they are validated by the results of the coupled-mode theory. The flatband resonant metasurfaces enabling a control of chiral thermal emission provide an efficient platform for spin-controlled light-matter interaction.

physics.optics↗

arXiv2025

Light matter interaction in van der Waals heterostructures with Mie voids

Recently introduced concept of Mie voids allows to enhance the field localization inside air cavities embedded in high-index materials. Mie voids provide an alternative approach to conventional dielectric resonators that confine optical fields within bulk high-index materials. Building on this concept, here we present a hybrid photonic platform that integrates monolayer WS2 with Mie void resonators patterned in a high-index Bi2Te3 substrate. By carefully aligning the dipolar void resonance with the excitonic transition of WS2, we achieve substantially enhanced photoluminescence and second-harmonic generation. Far-field imaging of the harmonic fields reveals spatially resolved hotspots that directly map localized resonant modes, with their positions tunable by cavity geometry and pump wavelength. This approach enables real-space control of nonlinear emission at the single-resonator level, offering a robust and reconfigurable platform for next-generation nonlinear photonics and surface-enhanced optical sensing.

physics.optics↗

arXiv2025

Intrinsically chiral exciton polaritons in an atomically-thin semiconductor

Photonic bound states in the continuum (BICs) have emerged as a versatile tool for enhancing light-matter interactions by strongly confining light fields. Chiral BICs are photonic resonances with a high degree of circular polarisation, which hold great promise for spin-selective applications in quantum optics and nanophotonics. Here, we demonstrate a novel application of a chiral BIC for inducing strong coupling between the circularly polarised photons and spin-polarised (valley) excitons (bound electron-hole pairs) in atomically-thin transition metal dichalcogenide crystals (TMDCs). By placing monolayer WS$_2$ onto the BIC-hosting metasurface, we observe the formation of intrinsically chiral, valley-selective exciton polaritons, evidenced by circularly polarised photoluminescence (PL) at two distinct energy levels. The PL intensity and degree of circular polarisation of polaritons exceed those of uncoupled excitons in our structure by an order of magnitude. Our microscopic model shows that this enhancement is due to folding of the Brillouin zone creating a direct emission path for high-momenta polaritonic states far outside the light cone, thereby providing a shortcut to thermalisation (energy relaxation) and suppressing depolarisation. Moreover, while the polarisation of the upper polariton is determined by the valley excitons, the lower polariton behaves like an intrinsic chiral emitter with its polarisation fixed by the BIC. Therefore, the spin alignment of the upper and lower polaritons ($\uparrow\downarrow$ and $\uparrow \uparrow$) can be controlled by $σ^+$ and $σ^-$ polarised optical excitation, respectively. Our work introduces a new type of chiral light-matter quasi-particles in atomically-thin semiconductors and provides an insight into their energy relaxation dynamics.

cond-mat.mes-hall↗

arXiv2025

Unconventional localization of light with Mie-tronics

Localization of light requires high-Q cavities or spatial disorder, yet the wave nature of light may open novel opportunities. Here we suggest to employ Mie-tronics as a powerful approach to achieve the hybridization of different resonances for the enhanced confinement of light via interference effects. Contrary to a conventional approach, we employ the symmetry breaking in finite arrays of resonators to boost the Q factors by in-plane multiple scattering. Being applied to photonic moire structures, our approach yields a giant enhancement of the Purcell factor via twist-induced coupling between degenerate collective modes. Our findings reveal how finely tuned cooperative scattering can surpass conventional limits, advancing the control of wave localization in many subwavelength systems.

physics.optics↗

arXiv2025

Nonlinear chiral light generation from resonant metasurfaces

Chiral nonlinear response has been explored for decades due to its extreme sensitivity to molecular and structural dissymmetry. Conventional approaches often require bulky systems and produce only static nonlinear chirality. Here, we report on a generic mechanism for the generation and control of nonlinear chiral light in resonant optical systems. We reveal that nonlinear resonant generation of circularly polarized light from achiral dielectric metasurfaces is extremely sensitive to the polarization state of the fundamental wave, and a resonant metasurface can produce light with arbitrary degree of nonlinear chirality (DNC). Experimentally, we demonstrate that the chirality of nonlinear radiation from one metasurface can be continuously tuned from DNC = -0.86 to DNC = 0.94 by simply varying the polarization angle of the incident wave. By further exploiting the instantaneous polarization state, nonlinear chirality has been switched in a delay time step of 3.2 fs, which is orders of magnitude more sensitive than the current state-of-the-art polarization modulation. These results promise to enrich our understanding of nonlinear processes in chiral structures and their manipulation with resonant photonic structures.

physics.optics↗

arXiv2025

Nonlinear chiral response from linearly achiral membrane metasurfaces

Chiral photonics aims to control and engineer light handedness for many applications in optical communications, biological and chemical sensing, and quantum technologies. While traditional approaches focus on engineering strong linear chiroptical response, nonlinear chiral phenomena remain largely unexplored. Here, we demonstrate experimentally a pronounced nonlinear chiral response in free-standing silicon membrane metasurfaces that are effectively achiral in the linear regime. By employing patterned membranes with both $C_4$-symmetry and intentionally broken in-plane symmetry, we reveal that strong nonlinear circular dichroism can be observed in third-harmonic generation. An unperturbed metasurface exhibits strong cross-polarized third-harmonic signal with nonlinear circular dichroism of the value $-0.83$, whereas in-plane symmetry breaking enables a co-polarized channel, and it reverses the sign of nonlinear circular dichroism that may be as large as the value $0.41$. Our findings suggest a novel approach for engineering nonlinear chiral responses in metasurfaces, complementing traditional approaches and paving the way towards advanced chiral metadevices.

physics.optics↗