2020/11/30 by B. Höckendorf, Bastian Höckendorf, Andreas Alvermann +3
Physics and Astronomy · #Degenerate energy levels #Floquet theory #Lattice (music) #Nonlinear Photonic Systems #Phase (matter) #Quantum Mechanics and Non-Hermitian Physics #Relative phase #Topological Materials and Phenomena #Topology (electrical circuits) #cond-mat.mes-hall
paper · pdf · doi:10.1063/5.0036494
published as APL Photonics 6, 010801 (2021) · 8 pages, 5 figures
openalex created_date 2020/11/23 · openalex publication_date 2021/01/01 · arxiv created 2021/01/21 · arxiv updated 2021/01/22 · openalex updated_date 2026/08/05
We propose a one-dimensional Floquet ladder that possesses two distinct topological transport channels with opposite directionality. The transport channels occur due to a Z2 non-Hermitian Floquet topological phase that is protected by time-reversal symmetry. The signatures of this phase are two pairs of Kramers degenerate Floquet quasienergy bands that are separated by an imaginary gap. We discuss how the Floquet ladder can be implemented in a photonic waveguide lattice and show that the direction of transport in the resulting waveguide structure can be externally controlled by focusing two light beams into adjacent waveguides. The relative phase between the two light beams selects which of the two transport channels is predominantly populated, while the angles of incidence of the two light beams determine which of the transport channels is suppressed by non-Hermitian losses. We identify the optimal lattice parameters for the external control of transport and demonstrate the robustness of this mechanism against disorder.