Papers by Author: Brigitte Boulard

Abstract: We report on fabrication and characterization of two different opal-like structures: (i) crystal exhibiting mechanochromism, i.e. change of colour when subjected to mechanical stress, composed of closely packed colloidal polystyrene particles (CPCP) embedded in a poly-dimethylsiloxane (PDMS) elastomeric matrix; (ii) metallo-dielectric systems (MDCS), based on the realization of inverse silica opal and following attachment of gold nanoparticles on the silica network of the inverse colloidal structure. Optical measurements, performed on the two structures, have demonstrated that: (i) when an horizontal strain is applied on the CPCP embedded in PDMS, a blue shift of the diffraction peak occurs as a function of the applied strain and (ii) MDCS have unique optical properties that combine the localized surface plasmon resonance (LSPR) of gold nanoparticles (Au NPs) with the photonic band gap features of colloidal crystal structures. Finally, preliminary results on MDCS used as SERS substrate evidence a higher increase of the Raman signal in respect to that observed for others metallic structures.

Abstract: Er3+-doped fluoride glass ceramics planar waveguides containing LaF3 or binary LaF3- ZrF4 nanocrystals have been fabricated by Physical Vapour Deposition (PVD). A quantitative analysis of the photoluminescence for the 1.5μm emission band of Er3+ ions has demonstrated that erbium ions are partitioned in both crystals and vitreous phase; the solubility of Er3+ in the segregated LaF3 nanocrystals can reach 30 mol% and the emission bandwidth has been found to be greater than that of the precursor glass (71nm at the half-height width). In order to increase the luminescence of Er3+, codoping with Yb3+ and Ce3+ has been investigated. The high Er3+ concentration and spectral width could make this nanostructured fluoride material suitable for planar amplifier in the C telecommunication band.