Fig. 1. The second-order photon correlation functions of single-atom g2τ, g1τ2 and g1'τ2 versus the delay time, with the spontaneous emission lifetime τsp=30ns, and the Rabi frequency Ω=12/τsp

Fig. 2. (a) Monitoring results of transmittance during the process of nanofiber drawing; (b) Measurement result of the waist region of nanofiber using scanning electron microscopy

Fig. 3. (a) Schematic diagram for single-end measurement of second-order photon correlation of fluorescence; (b) Schematic diagram for dual-end measurement of second-order photon correlation of fluorescence; (c) Image captured by CCD camera showing the relative position of the atomic ensemble and the nanofiber; (d) Spectrum of the fluorescence photons emitted by the atomic ensemble, with the red curve representing the fitting result using Lorentzian function

Fig. 4. Experimental results of second-order photon correlation measurements. (a) Results for fluorescence radiation from cold atoms coupling into nanofiber, measured via single-end detection; (b) Results for fluorescence radiation from cold atoms coupling into nanofiber, measured via dual-end detection

Fig. 5. Relationship between the normalized second-order photon correlation function gn2τ and the delay time τ . The characteristic correlation time obtained by fitting is τ0=1.6×103ns