文献类型：期刊文献

英文题名：Understanding the effects of dielectric medium, substrate, and depth on electric fields and SERS of quasi-3D plasmonic nanostructures

作者：Xu, Jiajie[1,3];Kvasnicka, Pavel[2];Idso, Matthew[1];Jordan, Roger W.[4];Gong, Heng[3];Homola, Jiri[2];Yu, Qiuming[1]

机构：[1]Univ Washington, Dept Chem Engn, Seattle, WA 98195 USA;[2]Acad Sci Czech Republic, Inst Photon & Elect, CR-18251 Prague, Czech Republic;[3]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[4]Texas A&M Univ, Dept Biomed Engn, College Stn, TX 77840 USA

年份：2011

卷号：19

期号：21

起止页码：20493

外文期刊名：OPTICS EXPRESS

收录：;EI(收录号：20114214430584);WOS:【SCI-EXPANDED(收录号:WOS:000296065700070)】；

基金：This work was supported in part by the University of Washington (UW) faculty start-up funds and the NOAA Ocean and Human Health Initiative (OHHI) funds. J.J.X. acknowledges a fellowship from the China Scholarship Council. R.W.J acknowledges the NNIN Research Experience for Undergraduates program supported by the NSF. Nanofabrication and SERS studies were performed at the Nanotech User Facility, the UW site of the National Nanotechnology Infrastructure Network (NNIN) supported by the NSF. This research was also supported by research grant KAN200670701 and by Praemium Academiae of the Academy of Sciences of the Czech Republic.

语种：英文

外文关键词：Nanostructures - Surface plasmons - Finite difference time domain method - Gold - ITO glass - Electric fields - Plasmonics - Fabry-Perot interferometers

摘要：The local electric field distribution and the effect of surfaceenhanced Raman spectroscopy (SERS) were investigated on the quasi-3D (Q3D) plasmonic nanostructures formed by gold nanohole and nanodisc array layers physically separated by a dielectric medium. The local electric fields at the top gold nanoholes and bottom gold nanodiscs as a function of the dielectric medium, substrate, and depth of Q3D plasmonic nanostructures upon the irradiation of a 785 nm laser were calculated using the three-dimensional finite-difference time-domain (3D-FDTD) method. The intensity of the maximum local electric fields was shown to oscillate with the depth and the stronger local electric fields occurring at the top or bottom gold layer strongly depend on the dielectric medium, substrate, and depth of the nanostructure. This phenomenon was determined to be related to the Fabry-Perot interference effect and the interaction of localized surface plasmons (LSPs). The enhancement factors (EFs) of SERS obtained from the 3D-FDTD simulations were compared to those calculated from the SERS experiments conducted on the Q3D plasmonic nanostructures fabricated on silicon and ITO coated glass substrates with different depths. The same trend was obtained from both methods. The capabilities of tuning not only the intensity but also the location of the maximum local electric fields by varying the depth, dielectric medium, and substrate make Q3D plasmonic nanostructures well suited for highly sensitive and reproducible SERS detection and analysis. (C) 2011 Optical Society of America