Topological on-chip lasers

A miniature on-chip laser is an essential component of photonic integrated circuits for a plethora applications, including optical communication and quantum information processing. However, the contradicting requirements small footprint, robustness, single-mode operation, high output power have led to multi-decade search optimal design. During this search, topological phases matter—conceived initially in electronic materials condensed matter physics—were successfully extended photonics applied designs. Benefiting from protection, edge mode can emit more efficiently robustly than one emitting trivial bulk mode. In addition, operation over large range excitation energies be achieved by strategically manipulating modes cavity. Perspective, we discuss recent progress lasers outlook on future research directions.