Akimov A V, Mukherjee A, Yu C L, Chang D E, Zibrov A S, Hemmer P R, Park H, Lukin M D
Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature. 2007 Nov 15;450(7168):402-6. doi: 10.1038/nature06230.
Control over the interaction between single photons and individual optical emitters is an outstanding problem in quantum science and engineering. It is of interest for ultimate control over light quanta, as well as for potential applications such as efficient photon collection, single-photon switching and transistors, and long-range optical coupling of quantum bits. Recently, substantial advances have been made towards these goals, based on modifying photon fields around an emitter using high-finesse optical cavities. Here we demonstrate a cavity-free, broadband approach for engineering photon-emitter interactions via subwavelength confinement of optical fields near metallic nanostructures. When a single CdSe quantum dot is optically excited in close proximity to a silver nanowire, emission from the quantum dot couples directly to guided surface plasmons in the nanowire, causing the wire's ends to light up. Non-classical photon correlations between the emission from the quantum dot and the ends of the nanowire demonstrate that the latter stems from the generation of single, quantized plasmons. Results from a large number of devices show that efficient coupling is accompanied by more than 2.5-fold enhancement of the quantum dot spontaneous emission, in good agreement with theoretical predictions.
控制单光子与单个光学发射器之间的相互作用是量子科学与工程领域的一个突出问题。这对于光量子的最终控制以及诸如高效光子收集、单光子开关和晶体管，以及量子比特的远程光学耦合等潜在应用都具有重要意义。最近，基于使用高精细光学腔来改变发射器周围的光子场，在实现这些目标方面已经取得了重大进展。在此，我们展示了一种无腔的宽带方法，通过在金属纳米结构附近对光场进行亚波长限制来设计光子 - 发射器相互作用。当单个CdSe量子点在靠近银纳米线的位置被光激发时，量子点的发射直接耦合到纳米线中的表面等离激元，使纳米线的两端发光。量子点发射与纳米线两端之间的非经典光子关联表明，后者源于单个量子化等离激元的产生。大量器件的结果表明，高效耦合伴随着量子点自发发射增强超过2.5倍，与理论预测高度吻合。
