Topography-induced variations of localized surface plasmon resonance in tip-enhanced Raman configuration

Abstract

We report on topography-induced changes of the localized surface plasmon resonance (LSPR) enhanced luminescence of gold tip on SrTiO 3 nanostructures with apertureless scanning near-field optical microscopy (aSNOM) in tip-enhanced Raman spectroscopy (TERS) configuration. Our experimental and simulated results indicate that the averaged refractive index of the dielectric environment of the tip apex containing both air and SrTiO 3 in variable volume ratios, is dependent on the topography of the sample. This reveals that the local topography has to be taken into consideration as an additional contribution to the position of the LSPR.

Plasmon-induced double-field-enhanced upconversion nanoprobes with near-infrared resonances for high-sensitivity optical bio-imaging

“…Au NP is one of frequently-used plasmonic materials and very suitable for biomedical applications due to its excellent physical stability and biocompatibility, as well as functionalizing for photothermal and photodynamic therapy [8]. The geometry and size of Au NP considerably affect LSPR wavelengths and LEF distributions of LSPR magnification [9]. Normally, most isotropic nanostructures such as Au nanosphere [10], Au nanoshell [11], and Au nanostar [12] have only one LSPR wavelength.…”