Tightly Focused Radially Polarized Beam for Propagating Surface Plasmon-Assisted Gap-Mode Raman Spectroscopy

摘要

Propagating surface plasmon (PSP) excitation, based on the total internal reflection configuration, was introduced into the nanoparticle (NP)-plane junction Raman spectroscopy. Experimental results demonstrated that silver nanospheres within the propagation region of PSP are effectively activated and detected by CCD camera due to their impressive Raman enhancement, which presents around 20 times improvement compared with the conventional NP-induced PSP/LSP co-enhanced Raman spectroscopy. This impressive Raman enhancement along with its high reproducibility of NP-plane junctions makes our configuration an attractive candidature for the PSP-assisted gap-mode surface-enhancement Raman spectroscopy and tip-enhanced Raman spectroscopy.