Lattice Resonances in Transdimensional WS2 Nanoantenna Arrays

Abstract

Mie resonances in high-refractive-index nanoparticles have been known for a long time but only recently have they became actively explored for control of light in nanostructures, ultra-thin optical components, and metasurfaces. Silicon nanoparticles have been widely studied mainly because of well-established fabrication technology, and other high-index materials remain overlooked. Transition metal dichalcogenides, such as tungsten or molybdenum disulfides and diselenides, are known as van der Waals materials because of the type of force holding material layers together. Transition metal dichalcogenides possess large permittivity values in visible and infrared spectral ranges and, being patterned, can support well-defined Mie resonances. In this Communication, we show that a periodic array of tungsten disulfide (WS2) nanoantennae can be considered to be transdimensional lattice and supports different multipole resonances, which can be controlled by the lattice period. We show that lattice resonances are excited in the proximity to Rayleigh anomaly and have different spectral changes in response to variations of one or another orthogonal period. WS2 nanoantennae, their clusters, oligomers, and periodic array have the potential to be used in future nanophotonic devices with efficient light control at the nanoscale.

Optical Constants of Several Multilayer Transition Metal Dichalcogenides Measured by Spectroscopic Ellipsometry in the 300–1700 nm Range: High Index, Anisotropy, and Hyperbolicity

“…These observations have led to a recently renewed interest in TMD optics and nanophotonics. This interest has grown even more after publication of several nanopatterning methods of TMDs and studies of optical phenomena in resulting TMD nanostructures. , Recent observations include high-index Mie resonances and anapole states in WS 2 nanodisks, optical anisotropy in TMD slabs , and nanocones, self-hybridization in TMD slabs , and nanotubes, optical modes in lattices of TMD nanostructures, improved second-harmonic generation in WS 2 and MoS 2 nanodisks, , high-index metamaterials, nanoholes down to ∼20 nm, dimer nanoantennas, and TMD metamaterials with atomically sharp edges …”

Nanostructured transition metal dichalcogenide multilayers for advanced nanophotonics

“…Figure 2b The peaks in the reflection spectra plotted in Figure 2b originate from nanodisk (D = 250 nm) arrays with various P red-shifts, when P increases from 200 nm to 600 nm. This resonance feature can be attributed to the geometrical lattice mode, since it is known that periodically arranged high-index dielectric nanodisks can exhibit geometrical lattice modes [27]. The data obtained from the nanodisk arrays with D = 200 nm are summarized in Supplementary Figure S1.…”

“…We begin our discussion by examining periodic arrays of TMD nanodisks and nanoholes, whose usefulness is based on the high refractive index of TMDs [4,9]. These systems possess optical resonances associated with the modes of individual elements, such as Mie resonances of individual disks, and lattice modes formed due to far-field couplings in periodic systems [4,8,13,26,27].…”

Optical Processes behind Plasmonic Applications

“…Arranging such lossy particles in a periodic array allows for stronger collective array resonances that can be easily tuned in a broad spectral range, mainly by the array period ( Figure 7 ). Transition metal dichalcogenides, including tungsten disulfide WS , possess large permittivity and support well-defined Mie resonances [ 88 , 89 ]. A periodic array of WS nanoantennas can control different multipole resonances via the lattice period [ 85 ], making it a potential tool for future nanophotonic devices.…”