Article

Plasmonics

, Volume 8, Issue 2, pp 225-231

First online:

Plasmonic Coupling Effect in Ag Nanocap–Nanohole Pairs for Surface-Enhanced Raman Scattering

  • Xiaolei WenAffiliated withDepartment of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China
  • , Zheng XiAffiliated withDepartment of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China
  • , Xiaojin JiaoAffiliated withDepartment of Electrical and Computer Engineering, University of Utah
  • , Wenhai YuAffiliated withDepartment of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China
  • , Guosheng XueAffiliated withDepartment of Optics and Optical Engineering, Bio-laser Laboratory, University of Science and Technology of China
  • , Douguo ZhangAffiliated withDepartment of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China
  • , Yonghua LuAffiliated withDepartment of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China
  • , Pei WangAffiliated withDepartment of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China Email author 
  • , Steve BlairAffiliated withDepartment of Electrical and Computer Engineering, University of Utah
    • , Hai MingAffiliated withDepartment of Optics and Optical Engineering, Anhui Key Laboratory of Optoelectronic Science and Technology, University of Science and Technology of China

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Abstract

A plasmonic coupling structure composed of Ag nanocap–nanohole pairs was fabricated through a novel and facile method. Both surface-enhanced Raman scattering (SERS) measurements and numerical simulations show that the cap-hole system produces much larger electric field enhancement and SERS signal than the isolated structures, which is due to the plasmonic coupling effect between the gap of the cap and the hole. Additionally, the plasmonic enhancement is sensitive to the gap size, which can be controlled by the Ag layer thickness during the evaporation process. A maximum enhancement factor of 1.1×108 can be obtained with optimized gap size.

Keywords

Plasmonic interaction Surface-enhanced Raman scattering (SERS) Hot spot Nanoscale gap