Silicon Mie resonators for highly directional light emission from monolayer MoS2

Abstract

Controlling light emission from quantum emitters has important applications ranging from solid-state lighting and displays to nanoscale single-photon sources. Optical antennas have emerged as promising tools to achieve such control right at the location of the emitter, without the need for bulky, external optics. Semiconductor nanoantennas are particularly practical for this purpose because simple geometries, such as wires and spheres, support multiple, degenerate optical resonances. Here, we start by modifying Mie scattering theory developed for plane wave illumination to describe scattering of dipole emission. We then use this theory and experiments to demonstrate several pathways to achieve control over the directionality, polarization state, and spectral emission that rely on a coherent coupling of an emitting dipole to optical resonances of a Si nanowire. A forward-to-backward ratio of 20 was demonstrated for the electric dipole emission at 680 nm from a monolayer MoS 2 by optically coupling it to a Si nanowire. Main text:Achieving control over the radiation properties of quantum emitters is key to improving efficiency and realizing new functionality in optoelectronic systems. Bulky optical components have been developed for many years and are extremely effective in controlling the angular, polarization, and spectral properties of light emission. Recent advances in the fields of metallic and dielectric optical metamaterials and nanoantennas have now also enabled effective integration of solid-state emitters and control elements into inexpensive platforms. 1-3 Such structures can manipulate light emission in the near-field of an emitter and thus hold a real promise to achieve even greater control over the emission process. For example, we will show how the undesired losses due to radiation of quantum emitters into a high-index substrate can be reduced by redirecting the emission upward with an antenna.Whereas structures based on noble metals are currently most advanced in manipulating light-matter interaction at the nanoscale, they typically are complex in shape, display undesired optical losses, and are not compatible with most semiconductor device processing technologies. High-index semiconductor antennas can circumvent these issues while providing complex electrical and optical functions. 2,4-14 Based on the mature fabrication infrastructure, silicon nanostructures appear particularly promising for optoelectronic applications. 4,[9][10][11][12][15][16][17] Semiconductor nanoparticles of simple geometric shapes have displayed directional scattering of plane waves when the renowned Kerker conditions are satisfied. 12,16,18 When these conditions are met, directionality is naturally achieved through the coherent excitation of electric and magnetic dipole resonances in the particle and tuning the interference of the associated scattered fields. 12,19,20 Thanks to their high refractive indices, semiconductor nanoparticles can satisfy the Kerker conditions in the visible spectral range. 16,18,21 Given the ever-in...

Magnetic and electric Mie-exciton polaritons in silicon nanodisks

“…This behaviour, that is well-known in highrefractive-index NDs, [49] can be exploited to achieve highly directional scattering when superimposing the MD and ED resonances. [36,37] To shed light on the nature of the observed resonances, we explored the system electrodynamics with the aid of the extended boundary-condition method (EBCM) for the evaluation of the scattering T matrix of nonspherical particles. [50] Since EBCM is based on expanding the incident and scattered fields in spherical waves, the method provides a straightforward way to characterise the resonances in terms of angular-momentum indices, (c) Calculated resonance decomposition for small (150 nm) and large-diameter (250 nm) nanodisks.…”

Enhanced excitation and emission from 2D transition metal dichalcogenides with all-dielectric nanoantennas

“…SiNPs of spherical shape can be fabricated chemically [33] or with fs-laser ablation [34]. In [33], [32], it has been shown that spherical SiNPs and Si nanowires can be placed on 2D TMDCs (WS2 and MoS2, respectively) without damaging their crystalline structure, where an additional thin layer of h-BN can be used for protection or isolation of 2D TNDCs [35].…”

All-Dielectric Resonant Meta-Optics Lightens up

“…Spatially complex light fields may still be accessible by constructing metasur-faces from individually directional dielectric nanoantennas or by exploiting coupling between the meta-atoms. A natural future step will also be to combine active control of spontaneous emission [58] with shaping of the spatial emission pattern [39,50] to implement dynamic control of the latter. Also, the possibility to control the polarization of the light emitted by active Mie-resonant nanostructures remains underutilized.…”