Toshiba Research Europe Ltd., Cambridge Research Laboratory, 208 Cambridge Science Park, Milton Road, Cambridge CB4 0GZ, UK.
Nat Commun. 2012 Jan 24;3:644. doi: 10.1038/ncomms1641.
Low-noise single-photon detection is a prerequisite for quantum information processing using photonic qubits. In particular, detectors that are able to accurately resolve the number of photons in an incident light pulse will find application in functions such as quantum teleportation and linear optics quantum computing. More generally, such a detector will allow the advantages of quantum light detection to be extended to stronger optical signals, permitting optical measurements limited only by fluctuations in the photon number of the source. Here we demonstrate a practical high-speed device, which allows the signals arising from multiple photon-induced avalanches to be precisely discriminated. We use a type of silicon avalanche photodiode in which the lateral electric field profile is strongly modulated in order to realize a spatially multiplexed detector. Clearly discerned multiphoton signals are obtained by applying sub-nanosecond voltage gates in order to restrict the detector current.
低噪声单光子探测是利用光子量子比特进行量子信息处理的前提。特别是，能够准确分辨入射光脉冲中光子数的探测器将在量子隐形传态和线性光学量子计算等功能中找到应用。更一般地说，这样的探测器将允许扩展量子光探测的优势到更强的光信号，从而允许仅由光源的光子数波动限制的光学测量。在这里，我们展示了一种实用的高速器件，它允许精确区分多个光致雪崩产生的信号。我们使用了一种硅雪崩光电二极管，其中横向电场分布被强烈调制，以实现空间多路复用探测器。通过施加纳秒级的电压门来限制探测器电流，可以获得清晰可辨的多光子信号。
