Zhang Xin, Xu Chang, Ren Zhongzhou
Department of Physics, Nanjing University, Nanjing, 210008, China.
School of Physics Science and Engineering, Tongji University, Shanghai, 200092, China.
Sci Rep. 2018 Feb 16;8(1):3140. doi: 10.1038/s41598-018-21481-z.
Demands for single-photon sources are ubiquitous in quantum information processing as well as in quantum metrology. In many protocols for producing single photons, a cavity-emitter configuration is used. In such cavity quantum electrodynamical systems, the cavity can enforce a well-defined output mode for the photon and enhance its collection efficiency, while the emitter is indispensable for single photon emission. Here we show the two cavity-one two-level emitter configuration can be used to produce exclusively photon pairs, with each photon in a separate mode. Conditioning on detecting a photon in one of the modes, one heralds with high fidelity a single photon in the other mode. Counterintuitively, upon decreasing the coupling of the emitter to one of the modes, the heralding fidelity can further increase.
单光子源在量子信息处理以及量子计量学中都有广泛需求。在许多产生单光子的协议中，会采用腔 - 发射体配置。在这种腔量子电动力学系统中，腔可为光子强制规定一个明确的输出模式并提高其收集效率，而发射体对于单光子发射是不可或缺的。在此我们展示了两个腔 - 一个两能级发射体的配置可用于专门产生光子对，且每个光子处于单独的模式。基于在其中一个模式中检测到光子，就能以高保真度预示在另一个模式中有单个光子。与直觉相反的是，当降低发射体与其中一个模式的耦合时，预示保真度会进一步提高。
