Self-Assembly and Optical Behavior of Mangetic-Plasmonic Nanostructures

摘要

We present a bottom-up method for the fabrication of nanostructured photonic media and demonstrate proof-of-principle using a multiphysics modeling approach. The method involves magnetic field-directed template-assidted self-assembly of magnetic-plasmonic core-shell particles (e.g. Fe_3O_4@Au) into extended particle superstructures that have a desired photonic functionality. The superparamagnetic core enables adaptive magnetophoretic control of particle motion and provides interparticle coupling that drives the assembly process. The plasmonic shell provides unique optical and photothermal properties of assembled structures. Monte Carlo analysis and full-wave field theory are combined to investigate self-assembly and optical properties of particle superstructures. We demonstrate the method for two different Fe_3O_4@Au particle assemblies: heptamer particle structures and ID particle chains. We demonstraet that the former supports Fano resonance behavior, while the latter exhibits extraordinary field enhancement and focused photothermal transduction.