Fig. 3

Single-photon emission from the topological bulk cavity. a Image of the device with a single QD located inside a ‘Q’-shaped topological bulk cavity. The device is illuminated by a halogen lamp and simultaneously the QD is excited by a 780 nm CW laser. The red dashed line indicates the topological interface, and the red solid line indicates the outer contour of the cavity. b PL spectra measured under different pump power. c Cross-correlation measurement of photons emitted from the XX–X cascade. Inset: Logarithmic plot of X and XX count rates as a function of excitation power. d Auto-correlation measurement for X or XX photons