Novel topological phases in gyromagnetic photonic crystals

Abstract

Topological phases have revolutionized both condensed matter and classical wave physics, and photonic systems have proven to be versatile platforms for exploring exotic topological phenomena. This thesis investigates novel topological phases in gyromagnetic photonic crystals, including an unpaired Dirac point, antichiral edge states, three-dimensional Chern insulators, amorphous topological insulators, and topological Anderson insulators. In Chapter 1, a brief history and classification of various topological phases in condensed matter and photonic systems are reviewed, and the topological invariants used in the subsequent chapters are introduced. Chapter 2 explores the photonic realization of Haldane models and the observation of an unpaired photonic Dirac point. Chapter 3 investigates the photonic realization of modified Haldane model and the observation of antichiral edge states. In Chapter 4, three-dimensional Chern insulators are studied, and linked and unlinked Fermi loop surface states are discovered. Chapter 5 examines disorder-induced topological phases in gyromagnetic photonic crystals, resulting in the experimental construction of an amorphous topological insulator and a topological Anderson insulator. Finally, Chapter 6 provides concluding remarks and proposes future research directions. Overall, this thesis contributes to the growing body of knowledge on topological phases in photonic systems and provides a platform for the development of new technologies based on these exotic phenomena.