Metallized tip amplification of near-field Raman scattering

Abstract

We have observed the amplification of near-field Raman scattering by using an apertureless near-field scanning optical microscope the tip of which is a 40 nm silver-layer-coated cantilever of an atomic force microscope. Localized surface plasmon polaritons are excited at the metallized tip apex of the cantilever thereby producing a field enhancement effect. We have unambiguously observed the amplification of the near-field signal due to the field enhancement by measuring the Raman spectra of Rhodamine 6G molecules adsorbed on 10 nm silver islands film when the metallized tip approached the surface of the sample. In addition, due to the nature of near-field optics, spectral mapping of Raman Scattering was attained with a 50 nm super-resolving power.