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Tuesday, August 15, 2017

Dynamic plasmonic nano-traps for single molecule surface-enhanced Raman scattering

Yuquan Zhang, Junfeng Shen, Zhenwei Xie, Xiujie Dou, Changjun Min Ting Lei, Jun Liu, Siwei Zhu and Xiaocong Yuan

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.

DOI

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