Chapter 10 Localized surface plasmon resonance-coupled photo-induced luminescence and surface enhanced raman scattering from isolated single Ag nano-aggregates

Abstract

This chapter discusses the novel surface-enhanced Raman scattering (SERS) mechanism that has been recently proposed. The main point of this chapter lies in the description about new findings on the strong optical correlations among the localized surface plasmon (LSP) resonance, SERS, and the continuum. It is found that (1) the continuum has clear a luminescence band structure; (2) the polarization-angle dependences of the LSP resonance, SERS and luminescence are the same as each other; (3) the changes in the band energy positions of the LSP resonance induce the same band changes in the luminescence; and (4) the LSP resonance having a higher quality factor yields stronger intensities of both SERS and luminescence. By combination of these new findings, one could succeed in the direct demonstration of the SERS mechanism: SERS is computed tomography (CT) resonance Raman scattering coupling to radiative decay of the LSP. The chapter demonstrates the mechanism of both the luminescence band variations and the temporal changes in the luminescence, LSP resonance, and SERS for isolated Ag nano-aggregates during the SERS active-to-inactive processes.