Fabrication of plasmonic nanoparticle structures on planar substrates
Lwin, Nyein Z.
Halas, Naomi J.
Master of Science thesis
Studying the optical properties of coupled plasmonic systems is important for both fundamental understanding and optimization of plasmon-enhanced optical sensing applications such as surface enhanced Raman scattering (SERS), near-field optical microscopy (NSOM) and surface plasmon resonance (SPR) sensing. Two nanoparticle structures of particular interest include nanoshell dimers and nanoparticles suspended over a metal film. We present a bench-top wet-chemistry method for nanoparticle dimer fabrication. The significant optical near-field enhancement in the gap between nanoparticles in a dimer structure could make it a powerful tool for enhanced spectroscopy applications. A simple geometry of nanoparticles suspended over a metal film is fabricated and its optical response is probed at various film thicknesses using optical transmission spectroscopy. A virtual resonance state emerged from interaction between discrete nanoparticle plasmons and the effective continuum of film plasmons shows a strong red-shift as the film thickness is decreased.
Electronics; Electrical engineering