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Item type:Publication, Access status: with files , Polaritonic quasi-bound states in the continuum in individual van der Waals nanoantennasThe study of strong light–matter interaction in van der Waals (vdW) materials is at the forefront of current research in physics and chemistry, and it can be enhanced dramatically by employing optical resonances. Here, we report on the first observation of quasi-bound states in the continuum (qBICs) realized via polaritonic interfering resonances in isolated WS2 nanodisks. We validate experimentally the existence of polaritonic qBICs driven by the intrinsic coupling of Mie resonances and vdW excitons. We observe exceptionally strong light–matter interaction with a measured Rabi splitting approaching 270 meV – the largest reported value among all transition metal dichalcogenide self-hybridized systems to date. The giant coupling strength stems from qBIC-induced in-plane field enhancement, which strongly interacts with in-plane excitonic dipoles while suppressing radiative losses. Polarization-controlled measurements further demonstrate selective excitation of qBIC through switching incident polarization to specific orthogonal configurations. The observed polarization-dependent coupling provides an additional degree of freedom to control the hybrid states’ spectral characteristics and spatial field distributions. Our demonstrations provide a pathway for engineering high-quality light–matter hybrid states in compact nanostructures, with potential applications in on-chip photonics, polaritonics, and quantum optics.Publicationtype: Journal Article22 5 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , An on-chip programmable valley optoelectronic nanocircuit(Nature Publishing Group, 2026-05-25); ; In transition metal dichalcogenides, the valley degree of freedom directly couples valley-polarized excitons, excited by circularly polarized light to valley-dependent chiral photons, enabling ultrafast light-driven valleytronics. However, achieving fully integrated valley optoelectronics, incorporating on-chip in situ generation, selective routing and electrical readout of valley-dependent chiral photons, remains an unresolved challenge. Here we present a valley-driven hybrid optoelectronic nanocircuit that integrates chirality-selective meta-waveguide photodetectors with transition metal dichalcogenides. At room temperature, our purposely designed meta-waveguide device generates near-unity valley-dependent chiral photons in the second-harmonic generation from an encapsulated tungsten disulfide monolayer and selectively couples them to unidirectional waveguide modes, achieving an exceptional polarization selectivity of 0.97. These valley-dependent waveguide modes were subsequently detected by atomically thin few-layer tungsten diselenide photodetectors, exclusively responsive to the above-bandgap upconverted photons, thereby enabling all-on-chip processing of valley-multiplexed images. Our demonstration bridges a critical gap in lightwave valleytronics, paving the way for compact, programmable and scalable valley information processing and fostering the development of light-based valleytronic quantum technologies.Publicationtype: Journal Article41 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Integration of 2D materials in radial van der Waals heterostructure metasurfaces(American Chemical Society (ACS), 2026-05-21); ; ; ; Two-dimensional semiconductors, such as monolayer transition metal dichalcogenides (TMD), exhibit strong excitonic transitions at room temperature and offer a platform for exploring light-matter interactions in nanoscale photonic systems. In this work, we demonstrate a compact and polarization-invariant photonic metasurface, fabricated from hexagonal boron-nitride (hBN) and based on radial bound states in the continuum (BIC), which are formed by radially distributed pairs of structurally asymmetric resonators. The metasurface employs multiple symmetry-breaking perturbations to support high-quality (Q) factor resonances within a radial footprint of 4.5 μm – approximately one-sixth of the area of previous hBN BIC metasurface implementations based on large periodic arrays. Compared to these approaches, the radial geometry furthermore achieves sizable Q-factors with a reduced footprint. By integrating the hBN photonic structure with a WS2 monolayer, we observe enhanced photoluminescence when its resonance is spectrally aligned with the exciton resonance, accompanied by signatures of discrete momentum-space patterns that identify the orbital-angular-momentum-carrying ring eigenmodes. These features persist over a wide range of excitation powers and show minimal linewidth broadening, indicating robust and spatially modulated exciton-photon coupling. This work establishes a scalable approach for generating hybrid photonic-excitonic states with momentum-space structure, offering opportunities for exciton localization, valley emission, spatially programmable light-matter interaction in 2D material platforms and compact luminescent devices based on 2D material integrated metasurfaces.Publicationtype: Journal Article31 11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Tunable polaritonic topologies generated by non-local photonic modes(Nature Publishing Group, 2026-05-12); ; ; ; Schwab, JulianPhotonic skyrmions are topological textures that exhibit remarkable resilience to environmental perturbations and support deeply subwavelength features, making them promising candidates for high-resolution microscopy, optical computing devices and ultrahigh-density information encoding. However, in contrast to free-space optical skyrmions, all existing approaches to generate polaritonic field skyrmions are limited by a lack of dynamic tunability. In general, without engineering the phase of the incident light, both their lattice site diameter and total topological charges remain fixed after fabrication. These constraints originate from a shared reliance on wavelength-dependent coupling structures or complex excitation conditions. To overcome these limitations, we introduce the concept of dynamically controllable polaritonic topologies generated by non-local photonic modes. Here we leverage quasi-bound states in the continuum resonances in dielectric metasurfaces to launch hyperbolic phonon polaritons in hexagonal boron nitride that interfere to create highly confined photonic skyrmion lattices with diameters down to 271 nm (λ/25). Thanks to the steep dispersion of hexagonal boron nitride, we can change the excitation frequency to achieve control over the size of individual photonic skyrmions within the same physical resonator structure. In addition, our platform is not limited to one type of topology but can generate optical meron lattices and kπ-twist skyrmions through straightforward variations in resonator shape, providing a feasible path towards skyrmion multiplexing and near-arbitrary topologies. The synergistic integration of resonant metasurfaces with polaritonic topologies has potential applications for nanophotonics, such as topological lasing, nonlinear optics and twistronics, as well as for condensed matter physics, such as Chern insulators and topological edge states.Publicationtype: Journal Article40 10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Chiral nonlinear polaritonics with van der Waals metasurfaces(2026-03-27); ; 21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Merging van der Waals materials and optical metasurfaces for cavity quantum electrodynamicsFlat optical metasurfaces are transforming photonics research by enabling new ways to control light in ultrathin, versatile photonic devices. The rise of quasi-bound states in the continuum (qBIC) metasurfaces has enabled tailored high-quality (Q) factor resonances in subwavelength nanostructured thin films, analogous to traditional optical cavities. In this perspective, we explore the emergence of cavity quantum electrodynamics (QED) in optical qBIC metasurfaces, specifically those constructed from van der Waals (vdW) layered materials. Because of their remarkable properties, vdW metasurfaces can support intrinsic optical resonances within the same active material hosting luminescent species, such as excitons or defects, leading to optimal light–matter coupling. This approach of self-hybridizing the cavity-emitter system into a single platform effectively overcomes limitations in on-chip integration of conventional cavities. Combining vdW materials with optically engineered qBIC metasurfaces opens exciting possibilities for exploring nanoscale light–matter interactions. Moreover, the distinctive features of vdW materials, from vertical heterostructures to twist-angle-dependent properties, offer a unique platform bridging the condensed matter physics of 2D materials and engineered nanophotonics. We propose that harnessing strong light–matter coupling in vdW-integrated qBIC metasurfaces will pave the way for next-generation nanoscale polaritonic devices.Publicationtype: Journal Article12 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Spatially encoded polaritonic ultra-strong coupling in gradient metasurfaces with epsilon-near-zero modes(2025-09-12)23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Ultrafast all-optical switching in nonlinear 3R-MoS₂ van der Waals metasurfaces(2025-09-02); 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A comparative analysis of plasmonic and dielectric metasurface sensing platforms powered by bound states in the continuum(2025-08-28); 13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Optical control of resonances in temporally symmetry-broken metasurfaces(2025-08-06); 24