Cascade enhancement of magnetic dipole emission and efficient collection of photons by the hybrid topological structure

High photon emission rate, high collection efficiency and stability are all important for single photon source applications. Here we demonstrate that both cascade enhancement of magnetic dipole emission and efficient collection of emitted photons can be realized simultaneously in a hybrid structure of a two-dimensional honeycomb topological photonic crystal containing dielectric nanodisk. The magnetic dipole resonance of nanodisk can effectively excite topological edgestate due to their near field overlapping. If a magnetic emitter is used to excite the nanodisk, then its magnetic dipole resonance can be viewed as a large equivalent dipole interacting with the edgestates, which achieves the cascade enhancement of the magnetic emitter. In addition, almost all the scattered photons around the nanodisk can be collected through topological edge state with the collection efficiency up to 95 mechanism may provide the practical applications of on-chip robust single photon sources and nanolasers.