title: Subwavelength direct laser patterning of conductive gold nanostructures by simultaneous photopolymerization and photoreduction.
abstract: This article presents a new method for fabricating highly conductive gold nanostructures within a polymeric matrix with subwavelength resolution. The nanostructures are directly written in a gold precursor-doped photoresist using a femtosecond pulsed laser. The laser energy is absorbed by a two-photon dye, which induces simultaneous reduction of gold in the precursor and polymerization of the negative photoresist. This results in gold nanoparticle-doped polymeric lines that exhibit both plasmonic effects, due to the constituent gold nanoparticles, and relatively high conductivity (within an order of magnitude of the bulk metal), due to the high density of particles within these lines. Line widths from 150 to 1000 nm have been achieved with this method. Various optically functional structures have been prepared, and their structural and optical properties have been characterized. The influence of laser intensity and scan speed on feature size have been studied and found to be in agreement with predictions of a mathematical model of the process.
authors.affiliation: Department of Electrical Engineering, Institute for Lasers, Photonics and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY 14260, USA.
authors.forename: Shobha
authors.initials: S
authors.lastname: Shukla
authors.forename: Xavier
authors.initials: X
authors.lastname: Vidal
authors.forename: Edward P
authors.initials: EP
authors.lastname: Furlani
authors.forename: Mark T
authors.initials: MT
authors.lastname: Swihart
authors.forename: Kyoung-Tae
authors.initials: KT
authors.lastname: Kim
authors.forename: Yong-Kyu
authors.initials: YK
authors.lastname: Yoon
authors.forename: Augustine
authors.initials: A
authors.lastname: Urbas
authors.forename: Paras N
authors.initials: PN
authors.lastname: Prasad
mesh_terms: D003460:Crystallization / Q000379:methods*; D006046:Gold / Q000737:chemistry* / Q000528:radiation effects*; D007834:Lasers; D046911:Macromolecular Substances / Q000737:chemistry / Q000528:radiation effects; D008422:Materials Testing; D008968:Molecular Conformation / Q000528:radiation effects; D049329:Nanostructures / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D010084:Oxidation-Reduction; D010316:Particle Size; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D046911:Macromolecular Substances; D006046:Gold