Topological phases and non-Hermitian topology in photonic artificial microstructures

Abstract

In the past few decades, the discovery of topological matter states has ushered in a new era in topological physics, providing a robust framework for strategically controlling the transport of particles or waves. Topological photonics, in particular, has sparked considerable research due to its ability to construct and manipulate photonic topological states via photonic artificial microstructures. Although the concept of topology originates from condensed matter, topological photonics has given rise to new fundamental ideas and a range of potential applications that may lead to revolutionary technologies. Here, we review recent developments in topological photonics, with a focus on the realization and application of several emerging research areas in photonic artificial microstructures. We highlight the research trend, spanning from the photonic counterpart of topological insulator phases, through topological semimetal phases, to other emerging non-Hermitian topologies.

Tuning Second Chern Number in a Four-Dimensional Topological Insulator by High-Frequency Time-Periodic Driving

“…These include introducing synthetic dimensions in two-dimensional (2D) or 3D systems, [32][33][34][35][36][37] mapping high-dimensional models onto lower-dimensional systems, [38][39][40][41][42][43] and implementing 4D lattices by constructing appropriate capacitive and inductive connections in electric circuits. [26,[44][45][46] Experimentally, 4D topological states have been realized in various systems such as acoustic lattices, [34] photonic crystals, [35,39,47] an angled optical superlattice with ultracold bosonic atoms, [38] and electric circuits. [26,[44][45][46] The modulation of topological phases has emerged as a significant topic in condensed matter physics.…”