Dual-polarization valley-like transport in dielectric photonic crystals.

Valley photonic crystal (VPC) waveguides possess strong immunity to backward scattering and robust transmission, originating from topologically protected edge states. Here, we propose a VPC/air/VPC sandwiched structure, and VPC possesses the common valley band gaps for TM and TE polarizations. By modifying the radii of the cylinders on both sides of the air channel, finite element method (FEM) simulations show the valley-locked waveguide modes with high flux are achieved, for both polarizations. Based on VPC/air/VPC sandwiched structure, we further design waveguide couplers and zigzag waveguide bends, and immunity to backward scattering and robust transmission are also verified. Our work finds a new method of designing photonic crystal waveguides, which support valley-like transport with enhanced flux and dual-polarization, making topological photonic devices easily to be integrated with conventional optical waveguides. • A VPC/air/VPC sandwiched structure, which possesses the common valley band gaps for both polarizations, is proposed. • Valley-locked waveguide modes for both polarizations with high flux are achieved. [ABSTRACT FROM AUTHOR]