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Nanoparticles of high-refractive-index materials like semiconductors enable strong confinement of light at the subwavelength scale because of the strong reflection from material boundaries and excitation of Mie resonances within the nanoscale-size particle. Recently, transition metal dichalcogenides (TMDCs) from the family of van der Waals layered materials have been shown to exhibit tailorable optical properties along with strong nonlinearity, high refractive index, and anisotropy originating from layered structure of the material. We envision that TMDCs are a promising material platform for designing metasurfaces and ultra-thin optical elements: these van der Waals materials show a strong spectral response on light excitations in visible and near-infrared ranges, and nanostructure characteristics can be controlled by nanoantenna dimensions and their arrangement [1]. Here, we investigate a periodic array of disk-shaped nanoantennas made of a TMDC material, tungsten disulfide, placed on top of a thin intermediate layer of high-index material such as silicon and low-index oxide substrate. Planar photonics with efficient subwavelength light control can be designed based on transdimensional lattices that operate in the translational regime between 2D and 3D [2]. Such transdimensional lattices include 3D-engineered nanoantennas supporting multipole Mie resonances and arranged in the 2D arrays with collective effects. The periodic arrangement of the nanoantenna array facilitates the strong coupling of light into the thin high-index layer. We show that the nanostructure resonances and coupling between nanoantennas and substrate in TMDC disk-shaped nanoantenna array can be controlled by the variation in silicon layer thickness and have a dependence on the presence of index-match superstrate cover.
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