Heimig, ConnorConnorHeimigBiechteler, JonasJonasBiechtelerCruciano, CristinaCristinaCrucianoGenco, ArmandoArmandoGencoWeber, ThomasThomasWeberHirler, MichaelMichaelHirlerGryb, DmytroDmytroGrybMenezes, Leonardo de S.Leonardo de S.MenezesValentini, GianlucaGianlucaValentiniManzoni, CristianCristianManzoniCerullo, GiulioGiulioCerulloMaier, Stefan A.Stefan A.MaierAntonov, Alexander A.Alexander A.AntonovSortino, LucaLucaSortinoTittl, AndreasAndreasTittl2026-06-082026-06-082026-05-21ACS nano 20 (22): 15927-15936 (2026)https://hdl.handle.net/11420/63374Two-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.en1936-086X2026221592715936American Chemical Society (ACS)https://creativecommons.org/licenses/by/4.0/Natural Sciences and Mathematics::539: Matter; Molecular Physics; Atomic and Nuclear physics; Radiation; Quantum PhysicsTechnology::620: Engineering::620.5: NanotechnologyJournal Articlehttps://doi.org/10.15480/882.1726910.1021/acsnano.5c2074010.15480/882.17269