Fabrication of Noble-metal Nanoparticle-doped SiO2-B2O3-P2O5 Waveguide Films

Abstract

In this article, we report the fabrication and the characterization of Pt/SiO2-B2O3-P2O5 and Au/SiO2-B2O3-P2O5 composite thin films suitable for planar lightwave circuits (PLCs). The host material was prepared by using flame hydrolysis deposition (FHD). Platinum was doped from colloidal solutions with concentrations of 500, 1000, and 2000 ppm. Gold was doped by sputtering with various deposition times. The samples displayed absorption peaks originating from the surface plasmon resonance (SPR) of the dopant metal particles. With increasing dopant particle size, the absorption peak shifted toward longer wavelength, and the full width at half maximum (FWHM) of the absorption band broadened. The Maxwell-Garnett theory was used to explain the size dependence of the plasmon peaks. The dopant metal particles were found to order as a monolayer within the silica matrix, opening the possibility for surface-plasmon-resonance-based waveguiding in optical devices.