Topological ring-cavity laser formed by honeycomb photonic crystals

We clarify theoretically that the topological ring-cavity (TRC) modes propagating along interface between two honeycomb-type photonic crystals distinct in topology can be exploited for achieving stable single-mode lasing, with maximal intensity larger than a whispering-gallery-mode counterpart by order of magnitude. Especially, we show TRC located at bulk bandgap center benefit maximally from gain profile since they are most concentrated and uniform ring cavity, that, inheriting Dirac-like dispersion states, separated frequency each other modes, both favoring intrinsically lasing. A mode running specific direction desired orbital angular momentum stimulated selectively injecting circularly polarized light. The laser proposed present work fabricated means advanced semiconductor nanotechnologies, which generates chiral beams ideal novel functions.