Fig. 2. Experimental realization of bulk WS₂ BIC metasurfaces.

a, Sketch of the experimental process including exfoliation of WS₂, nanopatterning via EBL and RIE and optical far-field spectroscopy. b, Scanning electron microscope micrographs of fabricated WS₂ metasurfaces with a scaling factor of S = 1.25 with different asymmetry parameters ΔL₀ and a uniform thickness of 80 nm. c, Transmittance spectra of WS₂ metasurfaces (shifted for visiblility) for different ΔL₀, showing the formation of the quasi-BIC modes. To show the uncoupled BIC modes, resonances were placed spectrally separated from the WS₂ exciton. d, Resonance Q factors extracted from the spectra in panel c showing a maximum Q factor of 374.