Direct Observation of Valley-polarized Topological Edge States in Designer Surface Plasmon Crystals
Abstract
The extensive research of two-dimensional layered materials has revealed that valleys, as energy extrema in momentum space, could offer a new degree of freedom for carrying information. Based on this concept, researchers have predicted valley-Hall topological insulators which could support valley-polarized edge states at non-trivial domain walls. Recently, several kinds of photonic or sonic crystals have been proposed as classical counterparts of valley-Hall topological insulators. However, direct experimental observation of valley-polarized edge states in photonic crystals is still difficult until now. Here, we demonstrate a designer surface plasmon crystal comprising metallic patterns deposited on a dielectric substrate, which can become a valley-Hall photonic topological insulator by exploiting the mirror-symmetry-breaking mechanism. Topological edge states with valley-dependent transport are directly visualized in the microwave regime. The observed edge states are confirmed to be fully valley-polarized through spatial Fourier transforms. Topological protection of the edge states at sharp corners is also experimentally demonstrated.
Keywords
Cite
@article{arxiv.1703.04570,
title = {Direct Observation of Valley-polarized Topological Edge States in Designer Surface Plasmon Crystals},
author = {Xiaoxiao Wu and Yang Meng and Jingxuan Tian and Yingzhou Huang and Hong Xiang and Dezhuan Han and Weijia Wen},
journal= {arXiv preprint arXiv:1703.04570},
year = {2017}
}