Institute of Physics, Karl-Franzens-University , Universitätsplatz 5, 8010 Graz, Austria.
Nano Lett. 2013 Sep 11;13(9):4257-62. doi: 10.1021/nl4019947. Epub 2013 Aug 26.
The coupling of optical emitters with a nanostructured environment is at the heart of nano- and quantum optics. We control this coupling by the lithographic positioning of a few (1-3) quantum dots (QDs) along plasmonic silver nanowires with nanoscale resolution. The fluorescence emission from the QD-nanowire systems is probed spectroscopically, by microscopic imaging and decay time measurements. We find that the plasmonic modes can strongly modulate the fluorescence emission. For a given QD position, the local plasmon field dictates the coupling efficiency, and thus the relative weight of free space radiation and emission into plasmon modes. Simulations performed with a generic few-level model give very good agreement with experiment. Our data imply that the 2D degenerate emission dipole orientation of the QD can be forced to predominantly emit to one polarization component dictated by the nanowire modes.
光发射器与纳米结构环境的耦合是纳米和量子光学的核心。我们通过在等离子体银纳米线上以纳米级分辨率定位几个（1-3）量子点（QD）来控制这种耦合。通过光谱探测、微观成像和衰减时间测量来探测 QD-纳米线系统的荧光发射。我们发现等离子体模可以强烈调制荧光发射。对于给定的 QD 位置，局部等离子体场决定了耦合效率，从而决定了自由空间辐射和发射到等离子体模的相对权重。使用通用的少数能级模型进行的模拟与实验非常吻合。我们的数据表明，可以迫使 QD 的二维简并发射偶极子取向主要发射到由纳米线模式决定的一个偏振分量。
