[23p-E303-1~15] 3.12 Nanoscale optical science and near-field optics

[23p-E303-1] Relationship between plasmon Fano resonance of asymmetric silver nanoparticle dimers and SERRS spectra of dye molecules adsorbed on dimer junctions

〇Tamitake Itoh¹, Yuko S. Yamamoto² (1.AIST, 2.JAIST)

Keywords:plasmon, SERS, Fano resonance

Raman detection of single molecule is realized by adsorbing molecules in the gaps between the dimer of silver nanoparticles or silver nanowires using interaction between plasmon resonance and molecular exciton resonance. This phenomenon is called surface-enhanced Raman scattering (SERS) and this gap is called a hotspot (HS). The envelope of the SERS spectrum is reproduced by the product of the plasmon resonance and the normal Raman spectrum. However, there are reports that the product fails to reproduce SERS spectra. The elucidation of the failure is important not only for improving the SERS mechanism but also for SERS application. We clarified that the failure is that the origin of enhanced electric field at HS changes from dipolar plasmon resonance to plasmon Fano resonance by changing the degree of asymmetry of the silver nanoparticles dimer.