Affiliation:
1. School of Physics State Key Lab for Mesoscopic Physics Academy for Advanced Interdisciplinary Studies Collaborative Innovation Center of Quantum Matter, and Nano‐optoelectronics Frontier Center of Ministry of Education Peking University Beijing 100871 P. R. China
Abstract
AbstractValleytronics in 2D transition metal dichalcogenides has raised a great impact in nanophotonic information processing and transport as it provides the pseudospin degree of freedom for carrier control. The imbalance of carrier occupation in inequivalent valleys can be achieved by external stimulations such as helical light and electric field. With metasurfaces, it is feasible to separate the valley exciton in real space and momentum space, which is significant for logical nanophotonic circuits. However, the control of valley‐separated far‐field emission by a single nanostructure is rarely reported, despite the fact that it is crucial for subwavelength research of valley‐dependent directional emission. Here, it is demonstrated that the electron beam permits the chirality‐selective routing of valley photons in a monolayer WS2 with Au nanostructures. The electron beam can locally excite valley excitons and regulate the coupling between excitons and nanostructures, hence controlling the interference effect of multipolar electric modes in nanostructures. Therefore, the separation degree can be modified by steering the electron beam, exhibiting the capability of subwavelength control of valley separation. This work provides a novel method to create and resolve the variation of valley emission distribution in momentum space, paving the way for the design of future nanophotonic integrated devices.
Funder
National Natural Science Foundation of China
National Key Research and Development Program of China
Subject
Mechanical Engineering,Mechanics of Materials,General Materials Science
Cited by
2 articles.
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