Mulitimodal Ultramicrospectroscope(MUMS): Imaging with Integrated Spectroscopies for Chemical and Biomolecular Identification: Scientific Progress and accomplishments

摘要

Nanoshells form the basic substrate for many of the surface enhanced spectroscopic studies undertaken under this MURI. We have developed a general facile technique to metallize dielectric nanoparticles. We hope this would widen the appeal of core-shell nanoparticles and simplify the production of larger quantities of core-shell nanoparticles. The SERS, and SERS-SEIRA techniques developed previously have been applied to elucidate reaction pathways in a metal catalyzed reaction, sensing small molecules that may not be bound to the nanoshell surface, and to determine the orientation of ds-DNA conjugated to nanoshells. Correlated single molecule SERS and electrical conductance measurements have been used to obtain the field strength in electromigrated junctions. We have studied a variety of different structures as potential sensing substrates. Nanotori, nanorods dimers and nanoparticle- nanowire coupled systems were studied. Symmetry breaking and the evolution of the optical and field enhancement properties of nanoshells, nanoeggs, nanocups and a coupled ring-disk system were investigated. In the ring-disk coupled system when symmetry is broken, the plasmonic equivalent of electromagnetically induced transparency (EIT) - plasmonically induced transparency and its characteristic Fano resonance can be observed. This intriguing phenomenon may give rise to new highly sensitive LSPR sensing modalities.