Figure 3: Result of second-order photon correlation measurement under autocorrelation configuration for the line. The Ti : Sapphire laser with the wavelength of 730 nm was used for the excitation. Observed peak separation of 12.2 ns corresponds to an excitation laser frequency of 82 MHz. Clear photon antibunching is observed at delay time , which indicates at most single photon is emitted per single excitation event.