Long-Range Directional Routing and Spatial Selection of High-Spin-Purity Valley Trion Emission in Monolayer WS₂

Abstract

Valley-dependent excitation and emission in transition metal dichalcogenides (TMDCs) have recently emerged as a new avenue for optical data manipulation, quantum optical technologies, and chiral photonics. The valleypolarized electronic states can be optically addressed through photonic spin−orbit interaction of excitonic emission, typically with plasmonic nanostructures, but their performance is limited by the low quantum yield of neutral excitons in TMDC multilayers and the large Ohmic loss of plasmonic systems. Here, we demonstrate a valleytronic system based on the trion emission in high-quantum-yield WS 2 monolayers chirally coupled to a low-loss microfiber. The integrated system uses the spin properties of the waveguided modes to achieve longrange directional routing of valley excitations and also provides an approach to selectively address valley-dependent emission from different spatial locations around the microfiber. This valleytronic interface can be integrated with fiber communication devices, allowing for merging valley polarization and chiral photonics as an alternative mechanism for optical information transport and manipulation in classical and quantum regimes.

Manipulating the light-matter interactions in plasmonic nanocavities at 1 nm spatial resolution

“…It constructs a concrete placement of emitters to manipulate the light at the nanoscale and respond quickly to the changes in the system. Through embedding emitters into the gap of plasmonic nanocavity, such as molecules 28 , quantum dots 29 , or transition metal dichalcogenides (TMDs) 30 – 32 , the desired configuration for manipulating light-matter interactions can be built. However, few studies on the vertical distribution of the actual system coupling in plasmonic nanocavities.…”

Tale of Two Resonances: Waveguide–Plasmon Coupling and High Q-Factor Engineering on the Nanoscale

“…Alternatively, selective excitation of CW or CCW modes can be achieved using a chiral MNPs under the excitation of circular polarized light. , By placing quantum dots or molecules in the gap between MNPs and a WGM cavity, chiral quantum routing or chiral sensing can be realized . SOI effects can also be used together with novel chiral materials, such as 2D materials with chiral excitons, for development of valleytronic devices with nonreciprocal functionalities. , …”

“…103 SOI effects can also be used together with novel chiral materials, such as 2D materials with chiral excitons, for development of valleytronic devices with nonreciprocal functionalities. 104,105 The difference in the fwhm's of CW and CCW WGMs induced by MNPs provides a foundation for studying non-Hermitian local sensors. 106 Specifically, molecules attached to the surface of a MNP introduce a perturbation (ϵ) of the system and, therefore, a frequency splitting Δf ∝ |ϵ| 1/N for the Nth order of exceptional points (EPs).…”

Directional Dipole Dice Enabled by Anisotropic Chirality

“…There are three types of elemental directional dipoles: circular dipole, Huygens dipole, and Janus dipole. The circular dipole (i.e., circularly polarized electric/magnetic dipole) can excite unidirectionally propagating guided waves via spin-momentum locking [22][23][24][25][26][27], with fascinating applications in topological photonics and non-Hermitian physics [28][29][30] as well as in designing novel nanophotonic devices [31][32][33][34][35]. The Huygens dipole can give rise to directional power flow in both the near and far fields [36][37][38][39][40], which can be employed to achieve vanished backscattering, cloaking, perfect refraction, perfect reflection, and near-field optical microscopy [41][42][43][44][45].…”