Reconfigurable Microwave Photonic Topological Insulator

Abstract: Using full 3D finite element simulation and underlining Hamiltonian models, we demonstrate reconfigurable photonic analogues of topological insulators on a regular lattice of tunable posts in a re-entrant 3D lumped element type system. The tunability allows dynamical {\it in-situ} change of media chirality and other properties via alteration of the same parameter for all posts, and as a result, great flexibility in choice of bulk/edge configurations. Additionally, one way photon transport without an external magnetic field is demonstrated. The ideas are illustrated by using both full finite element simulation as well as simplified harmonic oscillator models. Dynamical reconfigurability of the proposed systems paves the way to a new class of systems that can be employed for random access, topological signal processing and sensing.