McArthur Duncan, Papoff Francesco
Department of Physics, SUPA, University of Strathclyde, 107 Rottenrow, Glasgow, G4 0NG, UK.
Sci Rep. 2017 Oct 27;7(1):14191. doi: 10.1038/s41598-017-14250-x.
We analyze the enhancement of the rates of both the emission and the far field radiation for dipoles placed in the gap between a metallic nanorod, or nanosphere, and a metallic substrate. For wavelengths between 150 nm and 650 nm, the response of the gapped nanostructures considered in this work is dominated by few principal modes of the nanoparticle, which include self-consistently the effect of the substrate. For wavelengths shorter than 370 nm, the far field radiative enhancements of aluminum nanostructures are significantly higher than those for gold or silver. With aluminum, bright mode resonances are tunable over tens or hundreds of nanometers by changing the size of the nanoparticle and have far field radiative enhancements of up to three orders of magnitude. These results provide a road map to label-free detection of many emitters too weakly fluorescent for present approaches.
我们分析了置于金属纳米棒或纳米球与金属基底之间间隙中的偶极子的发射率和远场辐射率的增强情况。对于150纳米至650纳米之间的波长，本工作中所考虑的带隙纳米结构的响应主要由纳米颗粒的少数主要模式主导，其中自洽地包括了基底的影响。对于短于370纳米的波长，铝纳米结构的远场辐射增强显著高于金或银的远场辐射增强。使用铝时，通过改变纳米颗粒的尺寸，亮模式共振可在数十或数百纳米范围内调谐，并且具有高达三个数量级的远场辐射增强。这些结果为目前方法下荧光太弱的许多发射体的无标记检测提供了路线图。
