Abstract

Localized collective oscillation of conduction electrons on surface excited by light interacting with metallic nanostructure is referred as localized surface plasmon resonance (LSPR). It has been shown that the LSPR-induced strong electric field would enhance Raman signals efficiently to detect chemical and biological molecules. Therefore, the field of surface enhanced Raman spectroscopy (SERS) has attracted much attention recently. Previous studies have demonstrated LSPR-induced electric field enhancement can be produced in the gold nanoring structure, and the resonance wavelength can be tuned by different inner and outer diameters [1]. In addition, textured silicon substrate shows better scattering and absorption optical properties due to strong Mie resonance [2]. However, there are few reports on the advantages of combining nanoring with textured silicon structure for SERS application. In this work, we performed numerical simulations on the model of gold nanorings on silicon nanotubes substrate (Au-SiNTs) to study the dependence of resonance modes on outer/inner diameter ratio and verify it experimentally by both dark-field images and reflection spectra. Finally, this structure was fabricated and applied in SERS measurement.

© 2016 Japan Society of Applied Physics, Optical Society of America