Han Seb Moon

Telecom‐band quantum light sources are critical to the development of long‐distance quantum communication technologies. A high‐performance telecom‐wavelength biphoton source from a hot 87 Rb atomic vapor cell is reported. Time‐correlated biphotons are generated from the cascade‐type 5S 1/2 –5P 3/2 –4D 5/2 transition of 87 Rb via a spontaneous four‐wave mixing process. The maximum value of biphoton cross‐correlation to be 44(3) is achieved, under the condition of a high optical depth of 112(3), including two‐photon absorption, with a spectral width of approximately 300 MHz. The coincidence count rate of biphoton is estimated to be of the order of 38 000 cps mW −1 . It is believed that the telecom‐wavelength biphoton source from an atomic vapor cell can be applied in long‐distance quantum networks and practical quantum repeaters based on atom–photon interactions.