Guided-mode-resonance-coupled plasmonic-active SiO2 nanotubes for surface enhanced Raman spectroscopy

We demonstrate a surface enhanced Raman scattering (SERS) substrate by integrating plasmonic-active SiO2 nanotubes into Si3N4 gratings. First, the dielectric grating that is working under guided mode resonance (GMR) provides enhanced electric field for localized surface plasmon polaritons on the surface of metallic nanoparticles. Second, we use SiO2 nanotubes with densely assembled silver nanoparticles to provide a large amount of hot spots without significantly damping the GMR mode of the grating. Experimental measurement on Rhodamine-6G shows a constant enhancement factor of 8 similar to 10 in addition to the existing SERS effect across the entire surface of the SiO2 nanotubes. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4714710]