title: Polymer waveguide couplers based on metal nanoparticle-polymer nanocomposites.
abstract: In this work Au nanoparticles (AuNPs) are incorporated into poly(methyl methacrylate) (PMMA) waveguides to develop optical couplers that are compatible with planar organic polymer photonics. A method for growing AuNPs (of 10 to 100 nm in size) inside the commercially available Novolak resist is proposed with the intention of tuning the plasmon resonance and the absorption/scattering efficiencies inside the patterned structures. The refractive index of the MNP-Novolak nanocomposite (MNPs: noble metal nanoparticles) is carefully analysed both experimentally and numerically in order to find the appropriate fabrication conditions (filling factor and growth time) to optimize the scattering cross section at a desired wavelength. Then the nanocomposite is patterned inside a PMMA waveguide to exploit its scattering properties to couple and guide a normal incident laser light beam along the polymer. In this way, light coupling is experimentally demonstrated in a broad wavelength range (404-780 nm). Due to the elliptical shape of the MNPs the nanocomposite demonstrates a birefringence, which enhances the coupling to the TE mode up to efficiencies of around 1%.
authors.affiliation: UMDO (Unidad Asociada al CSIC-IMM), Instituto de Ciencia de Materiales, Universidad de Valencia, PO Box 22085, 46007 Valencia, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Signoretto
authors.forename: I
authors.initials: I
authors.lastname: Suárez
authors.forename: V S
authors.initials: VS
authors.lastname: Chirvony
authors.forename: R
authors.initials: R
authors.lastname: Abargues
authors.forename: P J
authors.initials: PJ
authors.lastname: Rodríguez-Cantó
authors.forename: J
authors.initials: J
authors.lastname: Martínez-Pastor