Nanophotonics Research Centre, Shenzhen University, Shenzhen 518060, China.
Nanoscale. 2017 Aug 3;9(30):10694-10700. doi: 10.1039/c7nr02406a.
Intense electric fields at the nanoscale are essential for single molecule surface-enhanced Raman scattering (SERS) detection. Such fields can be achieved in plasmonic nano-gaps between nanoparticles and metal films through hybridization of surface plasmons. The nano-gaps could be formed and dynamically controlled by using plasmonic tweezers; however, the aggregation of particles in the plasmonic field degrades each particle's enhancement and spoils the nanosized-spatial resolution. Here, dual-plasmonic tweezers are proposed and demonstrated to accurately control the number of nano-gaps and enhancement by tailoring a crater-shaped potential well in the nano-trap system. As the electric field in the nano-gap is intense, SERS spectral signatures of a single molecular level are probed simultaneously. These advantages point towards the implementation of enhanced Raman spectra, and broad applications in optical molecular detection.
纳米尺度的强电场对于单分子表面增强拉曼散射（SERS）检测至关重要。这种电场可以通过纳米颗粒和金属膜之间的表面等离子体激元杂交在等离子体纳米间隙中实现。纳米间隙可以通过等离子体镊子形成并动态控制；然而，在等离子体场中的颗粒聚集会降低每个颗粒的增强效果，并破坏纳米级空间分辨率。在这里，提出并演示了双等离子体镊子，通过在纳米陷阱系统中定制火山口形势阱来精确控制纳米间隙和增强的数量。由于纳米间隙中的电场很强，可以同时探测到单分子水平的 SERS 光谱特征。这些优势指向增强拉曼光谱的实现，并在光学分子检测中有广泛的应用。
