プラズモン増強場の形成と光反応

摘要

Highly homogeneous arrays of metallic nanostructures were fabricated on glass substrates using electron-beam lithography and lift -off techniques. Optical properties of the fabricated structures related to localized surface plasmons (LSP), and their dependencies on geometries were studied by optical extinction spectroscopy. Spectral tuning of LSP resonant bands in a wide spectral range, from visible to infrared wavelengths, can be accomplished by tailoring of the nanostructure dimensions and aspect ratios. We also described large homogeneous clusters of gold nanoblocks which allow observation of strong photoluminescence excited via two-photon absorption by using femto second laser. The key feature of the structures is intense near-field existing in few nanometer-wide nanogaps between the nanoblocks, and associated with collective LSP modes of the cluster. We introduce, furthermore, that nanoparticle plasmons could induce detectable two -photon absorption even under irradiation by incoherent continuous-wave sources which was found according to study two-photon polymerization of the photoresist surrounding the nano-structures.