Robust single photon generation in topological coupled cavity-waveguide QED system

For implementation of large-scale quantum computation, we need on-chip single photon sources compatible with integrated photonic circuits. In particular, robustness of topological photonic systems against structural defects or disorder enables us to obtain reliable operations of photonic devices. In this work, we present a robust single photon source based on the resonant excitation of an InAs/GaAs quantum dot embedded in topological coupled cavity-waveguide system. The emission dynamics of the system is investigated by numerically solving master equation for reduced density matrix of effective cavity quantum electrodynamics system. The results show that single photons can be generated with a purity of about 0.8 and a source brightness of around 11 % under resonant excitation. Compared with non-topological system, the proposed topological source exhibits the single photon emission immune to structural defects. Such a robustness of emission performance is the key advantage of the proposed system over non-topological ones, offering practical applicability for quantum technology.