Authors
Fei Gao, Haoran Xue, Zhaoju Yang, Kueifu Lai, Yang Yu, Xiao Lin, Yidong Chong, Gennady Shvets, Baile Zhang
Publication date
2018/2/1
Journal
Nature Physics
Volume
14
Issue
2
Pages
140-144
Publisher
Nature Publishing Group UK
Description
Recently discovered, valley photonic crystals (VPCs) mimic many of the unusual properties of two-dimensional (2D) gapped valleytronic materials,,,,,,. Of the utmost interest to optical communications is their ability to support topologically protected chiral edge (kink) states,,,,,, at the internal domain wall between two VPCs with opposite valley-Chern indices. Here we experimentally demonstrate valley-polarized kink states with polarization multiplexing in VPCs, designed from a spin-compatible four-band model. When the valley pseudospin is conserved, we show that the kink states exhibit nearly perfect out-coupling efficiency into directional beams, through the intersection between the internal domain wall and the external edge separating the VPCs from ambient space. The out-coupling behaviour remains topologically protected even when we break the spin-like polarization degree of freedom (DOF), by introducing …
Total citations
20172018201920202021202220232024335647966847654
Scholar articles