Experimental quasi-single-photon transmission from satellite to earth

Date: 2013-05-04
Authors Juan Yin, Yuan Cao, Shu-Bin Liu, Ge-Sheng Pan, Jin-Hong Wang, Tao Yang, Zhong-Ping Zhang, Fu-Min Yang, Yu-Ao Chen, Cheng-Zhi Peng, and Jian-Wei Pan
Journal No. Optics Express 22, 20032(2013)
Abstract Free-space quantum communication with satellites opens a promising avenue for global secure quantum network and large-scale test of quantum foundations. Recently, numerous experimental efforts have been carried out towards this ambitious goal. However, one essential step - transmitting single photons from the satellite to the ground with high signal-to-noise ratio (SNR) at realistic environments - remains experimental challenging. Here, we report a direct experimental demonstration of the satellite-ground transmission of a quasi-single-photon source. In the experiment, single photons (∼0.85 photon per pulse) are generated by reflecting weak laser pulses back to earth with a cube-corner retro-reflector on the satellite CHAMP, collected by a 600-mm diameter telescope at the ground station, and finally detected by single-photon counting modules after 400-km free-space link transmission. With the help of high accuracy time synchronization, narrow receiver field-of-view and high-repetition-rate pulses (76 MHz), a SNR of better than 16:1 is obtained, which is sufficient for a secure quantum key distribution. Our experimental results represent an important step towards satellite-ground quantum communication.