Lounis B, Moerner W E
Department of Chemistry, Stanford University, California 94305-5080, USA.
Nature. 2000 Sep 28;407(6803):491-3. doi: 10.1038/35035032.
The generation of non-classical states of light is of fundamental scientific and technological interest. For example, 'squeezed' states enable measurements to be performed at lower noise levels than possible using classical light. Deterministic (or triggered) single-photon sources exhibit non-classical behaviour in that they emit, with a high degree of certainty, just one photon at a user-specified time. (In contrast, a classical source such as an attenuated pulsed laser emits photons according to Poisson statistics.) A deterministic source of single photons could find applications in quantum information processing, quantum cryptography and certain quantum computation problems. Here we realize a controllable source of single photons using optical pumping of a single molecule in a solid. Triggered single photons are produced at a high rate, whereas the probability of simultaneous emission of two photons is nearly zero--a useful property for secure quantum cryptography. Our approach is characterized by simplicity, room temperature operation and improved performance compared to other triggered sources of single photons.
产生非经典光态具有重要的科学和技术意义。例如，“压缩”态能够实现比使用经典光时更低噪声水平的测量。确定性（或触发式）单光子源表现出非经典行为，即它们能在用户指定的时间以高度确定性发射恰好一个光子。（相比之下，诸如衰减脉冲激光器这样的经典光源按照泊松统计发射光子。）确定性单光子源可用于量子信息处理、量子密码学以及某些量子计算问题。在此，我们利用固体中单个分子的光泵浦实现了一个可控的单光子源。触发式单光子以高速率产生，而同时发射两个光子的概率几乎为零——这是安全量子密码学的一个有用特性。我们的方法具有简单、室温操作以及与其他触发式单光子源相比性能更优的特点。
