| Light–matter interaction in van der Waals Mie-void heterostructures. (a) Schematic of a van der Waals heterostructure shows a monolayer WS₂ stacked on a Bi₂Te₃ Mie void resonator. The air cavity supports surface-localized Mie resonances confined within the void and concentrated near the top interface, enabling strong spatial overlap with the atomically thin WS2 layer. (b) A scanning electron microscopy (SEM) image of a fabricated Bi₂Te₃ Mie void illustrates the circular cavity geometry with smooth sidewalls and well-defined depth and radius. (c) Simulated resonance behaviour of Bi2Te3 Mie voids with systematically varied cavity geometry shows continuous and geometry-controlled tuning of the optical resonance across the visible–near-infrared spectral range while maintaining robust modal confinement. (d) Photoluminescence (PL) mapping of a monolayer WS₂ transferred onto a Bi2Te3 Mie void array reveals pronounced emission enhancement at resonant void locations compared to flat or off-resonant regions, directly evidencing resonance-mediated light–matter interaction. (e) Correlated experimental second-harmonic generation WS2 imaging and simulated electric-field distributions for representative Mie voids demonstrates that strong nonlinear emission originates from dipole-dominated surface-localized modes with maximal field confinement near the WS₂ interface. Credit: Z. Lu et al., doi 10.1117/1.AP.8.2.026002 |
