Topological valley transport under long-range deformations

Abstract

Edge states protected by bulk topology of photonic crystals offer exciting means to study spintronics, and their robustness to short-range disorder makes robust information transfer possible. Here, we investigate topological transport under long-range amorphous deformation without external magnetic field. Vertices of each regular hexagon in a C3-symmetric crystalline structure are shifted randomly. Despite the existence of unpredictable scattering, topological edge modes are determined by statistic behavior of the whole structure. Photonic density of states as well as the Fourier transform can be used to distinguish the topological properties. We further designed and fabricated samples working in the microwave band. The measured transmission spectrum reveals the existence of robust topological states in the amorphous system. This work proves the robustness of bulk topology, points to the study of topological properties of structures undergoing amorphous deformation, and may open the way for exploiting topological insulators in materials with different phases.

Hybrid topological guiding mechanisms for photonic crystal fibers

“…Numerical studies that demonstrate the robustness of these topological states versus conventional designs for Newtonian systems are found in [50,[53][54][55]. Theoretical studies that demonstrate the existence of these modes under disorder are found in [56,57].…”

Hybrid topological guiding mechanisms for photonic crystal fibers

“…Numerical studies that demonstrate the robustness of these topological states versus conventional designs for Newtonian systems are found in [49,[52][53][54]. Theoretical studies that demonstrate the existence of these modes under disorder are found in [55,56].…”

Topological Valley Photonics: Physics and Device Applications

“…However, valley‐Hall lattices are not limited to these designs and can be realized in other settings, such as the kagome lattice, [ 71,72 ] the square lattice, [ 73–75 ] and even amorphous systems. [ 76,77 ] Due to this simplicity and flexibility in design, photonic valley‐Hall systems have been widely studied, and various new phenomena and applications have been discovered. In the next four sections, we will review several important aspects of photonic valley‐Hall systems, showing that they are simple but effective.…”

“…[ 81 ] In fact, valley transport is even found to exist in systems without long‐range order. [ 76,77 ] Thus, as long as the short‐range order around the interface approximately holds, the backscattering and localization induced by disorders would not be significant, and the robustness of kink states would be approximately valid. In addition, to engineer fully topologically protected valley transport, researchers have suggested using chiral vortex in a nonlinear polariton lattice.…”