Fabricating plasmonic waveguides and resonant structures by laser printing of single nanoparticles

GARGIULO, JULIÁN; CORTÉS, EMILIANO; STEFANI, FERNANDO D.

Conferencia; Discussions on Nano & Mesoscopic Optics; 2015

Laser printing is a top-down technique based on optical forces and colloidal interactions that allows patterning andimmobilization of nanoparticles onto surfaces with precision of a few tens of nanometers. [1] The technique is aversatile tool for the fabrication of arbitrary nanoparticle arrays in the mesoscopic scale, created by sequentialprinting of single particles. [2], [3]However, printing nanoparticles closer than a few hundreds of nanometers in a controlled way remains an openchallenge. Surpassing this limitation is of fundamental importance when metallic nanoparticles are used, because itwould enable the electromagnetic coupling of nanoparticles, making possible the fabrication of plasmonicwaveguides and the tailoring of plasmonic resonances for electrical field, fluorescence or Raman enhancement.It has been reported that a possible cause for the limitation on the minimum interparticle separation distance is thescattered light from already printed nanoparticles. This phenomenon is called optical binding and strongly dependson the polarization of the incident light. [4] In this work we present different strategies for surpassing this limitation.Firstly, we study the influence of different polarization schemes on the printing process. Secondly, we study the roleof electrostatic repulsion between nanoparticles by exchanging the capping molecules of the printed ones. Finally,we present a bi-metallic laser printing technique. Using two types of nanoparticles with spectrally separatedplasmon resonances can lead to weaker repulsive forces.