Edge-oriented and steerable hyperbolic polaritons in anisotropic van der Waals nanocavities

Authors

Zhigao Dai, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, P. R. China
Guangwei Hu, CUNY Advanced Science Research CenterFollow
Guangyuan Si, College of Information Science and Engineering, Northeastern University, Shenyang, China
Qingdong Ou, Department of Materials Science and Engineering, ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Clayton, Victoria, Australia
Qing Zhang, Department of Electrical and Computer Engineering, National University of Singapore
Sivacarendran Balendhran, School of Physics, The University of Melbourne, Parkville, Australia
Fahmida Rahman, School of Engineering, RMIT University, Melbourne, Australia
Bao Yue Zhang, School of Engineering, RMIT University, Melbourne, Australia
Jian Zhen Ou, School of Engineering, RMIT University, Melbourne, Australia
Guogang Li, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, P. R. China
Andrea Alù, CUNY Advanced Science Research CenterFollow
Cheng-Wei Qiu, Department of Electrical and Computer Engineering, National University of SingaporeFollow
Qiaoliang Bao, Department of Materials Science and Engineering, ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Clayton, Victoria, AustraliaFollow

Document Type

Article

Publication Date

2020

Abstract

Highly confined and low-loss polaritons are known to propagate isotropically over graphene and hexagonal boron nitride in the plane, leaving limited degrees of freedom in manipulating light at the nanoscale. The emerging family of biaxial van der Waals materials, such as α- MoO₃ and V₂O₅, support exotic polariton propagation, as their auxiliary optical axis is in the plane. Here, exploiting this strong in-plane anisotropy, we report edge-tailored hyperbolic polaritons in patterned α-MoO₃ nanocavities via real-space nanoimaging. We find that the angle between the edge orientation and the crystallographic direction significantly affects the optical response, and can serve as a key tuning parameter in tailoring the polaritonic patterns. By shaping α-MoO₃ nanocavities with different geometries, we observe edge-oriented and steerable hyperbolic polaritons as well as forbidden zones where the polaritons detour. The lifetime and figure of merit of the hyperbolic polaritons can be regulated by the edge aspect ratio of nanocavity.

Comments

This article was originally published in Nature Communications, available at https://doi.org/10.1038/s41467-020-19913-4

This work is distributed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).