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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 4 - 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 9 - 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 , 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 , Optical control of resonances in temporally symmetry-broken metasurfaces(2025-08-06); 23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Fabrication optimization of van der Waals metasurfaces: inverse patterning boosts resonance quality factorVan der Waals (vdW) materials have garnered growing interest for use as nanophotonic building blocks that offer precise control over light-matter interaction at the nanoscale, such as optical metasurfaces hosting sharp quasi-bound states in the continuum resonances. However, traditional fabrication strategies often rely on lift-off processes, which inherently introduce imperfections in resonator shape and size distribution, ultimately limiting the resonance performance. Here, an optimized fabrication approach for vdW-metasurfaces is presented that implements inverse patterning of the etching mask, resulting in increased resonator quality solely limited by the resolution of the electron beam lithography resist and etching. Applying this inverse fabrication technique on hexagonal boron nitride (hBN), quality (Q) factors exceeding 10³ in the visible spectral range are demonstrated, significantly surpassing previous results shown by lift-off fabricated structures. Additionally, the platform's potential as a biosensor is displayed, achieving remarkable sensitivity and figure of merit of 220 in a refractive index sensing experiment. The inverse technique is applied to create chiral metasurfaces from hBN, using a two-height resonator geometry to achieve up to 50% transmittance selectivity. This inverse lithography technique paves the way toward high-performances vdW-devices with high-Q resonances, establishing hBN as a cornerstone for next-generation nanophotonic and optoelectronic devices.Publicationtype: Journal Article21 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Ultrafast tuning of radiative optical losses in quasi-bound states in the continuum(2025-06); ; Optically resonant metasurfaces provide a convenient way to enhance light-matter interactions in a confined spectral region, boosting nonlinear phenomena, sensitivity in biosensing, or spontaneous emission. Specifically, structures based on symmetry-protected quasi-bound states in the continuum (qBICs) have emerged as a popular framework to design resonant metasurfaces, as their structure does not only determine the resonance's wavelength, but also the quality-factor through the asymmetry of each unit cell [1].Publicationtype: Conference Paper15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Angular dispersion suppression in deeply subwavelength phonon polariton bound states in the continuum metasurfaces(Nature Publishing Group, 2025-05-16); ; 20 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , All-dielectric structural coloration empowered by bound states in the continuumThe technological requirements of low-power and high-fidelity color displays have been instrumental in driving research into advanced coloration technologies. At the forefront of these developments is the implementation of dye-free approaches, which overcome previous constraints related to color resolution and fading. Resonant dielectric nanostructures have emerged as a promising paradigm, showing great potential for high efficiency, high color saturation, wide gamut palette, and image reproduction. However, they still face limitations related to color accuracy, purity, and simultaneous brightness tunability. Here, we demonstrate an all-dielectric metasurface empowered by photonic bound states in the continuum (BICs), which supports sharp resonances throughout the visible spectral range, ideally suited for producing a wide range of structural colors. The metasurface design consists of TiO<inf>2</inf> ellipses with carefully controlled sizes and geometrical asymmetry, allowing versatile and on-demand variation of the brightness and hue of the output colors, respectively.Publicationtype: Journal Article9