Profiling the near field of a plasmonic nanoparticle with Raman-based molecular rulers.
The enhanced local optical fields at the surface of illuminated metallic nanoparticles and nanostructures are of intense fundamental and technological interest. Here we report a self-consistent measurement of the spatial extent of the fringing field above a plasmonic nanoparticle surface. Bifunctional DNA-based adsorbate molecules are used as nanoscale optical rulers, providing two distinct surface enhanced Raman scattering signals that vary independently in intensity as a function of distance from the nanoparticle surface. While the measurement technique is calibrated on gold nanoshell surfaces with controlled and predictable electromagnetic nanoenvironments, this approach is broadly adaptable to a wide range of plasmonic geometries.
Lal
Surbhi
S
Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005-1892, USA.
Grady
Nathaniel K
NK
Goodrich
Glenn P
GP
Halas
Naomi J
NJ
D004247:DNA / Q000032:analysis* / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D020349:Surface Plasmon Resonance / Q000379:methods*
D004247:DNA