Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna
Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna
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DOI：
10.1038/nphoton.2009.187
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发表时间：
2009-11-01
期刊：
影响因子：
35
通讯作者：
Moerner, W. E.
中科院分区：
文献类型：
--
作者：
Kinkhabwala, Anika;Yu, Zongfu;Moerner, W. E.
由于光和纳米级物体（如单分子）之间的尺寸不匹配，因此能够控制光分子相互作用非常重要（1-4）。等离子体纳米天线在共振泵浦时产生高度增强的局部场，导致增加的拉曼散射（5），但是否发生荧光增强取决于多种因素。虽然尖锐的金属尖端（6）和胶体（7，8）可以增强荧光，但是光刻制造的蝴蝶结纳米天线（9）的高度增强的光场提供了更可控且更易于集成的结构。使用金蝴蝶结，我们观察到单个分子的荧光增强高达1，340倍，比以前报道的高10倍（7，8，10 -22）。电磁模拟表明，这是大大增强的吸收和增加的辐射发射率的结果，导致增强的固有量子效率的估计因子为9，尽管额外的非辐射欧姆效应。因此，蝴蝶结纳米天线显示出巨大的潜力，高对比度的选择单一的纳米发射器。
Owing to the size mismatch between light and nanoscale objects such as single molecules, it is important to be able to control light-molecule interactions(1-4). Plasmonic nanoantennas create highly enhanced local fields when pumped resonantly, leading to increased Raman scattering(5), but whether fluorescence enhancement occurs depends upon a variety of factors. Although sharp metal tips(6) and colloids(7,8) can enhance fluorescence, the highly enhanced optical fields of lithographically fabricated bowtie nanoantennas(9) provide a structure that is more controllable and amenable to integration. Using gold bowties, we observe enhancements of a single molecule's fluorescence up to a factor of 1,340, ten times higher than reported previously(7,8,10-22). Electromagnetic simulations reveal that this is a result of greatly enhanced absorption and an increased radiative emission rate, leading to enhancement of the intrinsic quantum efficiency by an estimated factor of nine, despite additional non-radiative ohmic effects. Bowtie nanoantennas thus show great potential for high-contrast selection of single nanoemitters.