Second-order interference of two independent and tunable single-mode continuous-wave lasers

Liu Jianbin^{1, 2}, Wei Dong^{3, †,}, Chen Hui^{1, 2}, Zhou Yu³, Zheng Huaibin^{1, 2, 3}, Gao Hong³, Li Fu-Li³, Xu Zhuo^{1, 2}

Measured two-photon coincidence counts when the frequency difference is (a) 189 MHz, (b) 461 MHz, (c) 1.11 GHz, () 3.0 GHz. CC: two-photon coincidence count. t₁ − t₂: time difference between two single-photon detection event for a two-photon coincidence count. The collection time for each figure is 120 s.