Spectroscopie Mössbauer, propriétés magnétiques et optiques non-linéaires de xérogels dopés par des nanoparticules ferriques

Poster (2006)

High transmission efficiency for surface plasmon resonance by use of a dielectric grating

in Applied Optics (2005), 44(28), 6017-6022

The efficiency of the transmission of surface plasmon waves by use of a dielectric diffraction grating is discussed. The Kretschmann device allows us to obtain a surface plasmon resonance that consists of ... [more ▼]

The efficiency of the transmission of surface plasmon waves by use of a dielectric diffraction grating is discussed. The Kretschmann device allows us to obtain a surface plasmon resonance that consists of an absorption peak in the reflection spectrum. When surface plasmon resonance occurs, the TM-polarization mode of the incident electromagnetic wave is neither transmitted nor reflected. The procedure to transform an absorption peak into a transmission peak is described. Transmittivity of 68% is obtained for a simple structure that consists of a thin-film layer of Ag coated on a volume diffraction grating and embedded between two dielectric media. The results presented herein were obtained by numerical simulations that were carried out by use of an algorithm based on the rigorous coupled-wave theory. [less ▲]

Narrow band-width wavelength filter by guided mode resonance

in Optical Engineering : The Journal of the Society of Photo-Optical Instrumentation Engineers (2004), 43(11), 2631-2639

Simple resonant structures that permit holographic reflection filtering are studied. The filters under study work under a 45-deg incidence for a wavelength of λ=632.8 nm, a condition useful for future ... [more ▼]

Simple resonant structures that permit holographic reflection filtering are studied. The filters under study work under a 45-deg incidence for a wavelength of λ=632.8 nm, a condition useful for future inclusion in substrate mode systems. First, the influence of the structural parameters of the grating and the waveguide on the position and the shape of the resonance peaks are studied by numerical computation. The numerical results, obtained within the rigorous coupled wave theory, are compared with the measured response of some filters. These filters contain a grating recorded by holography deposited on the substrate. In the case of the bilayer filter, a waveguide is introduced between the grating and the substrate. Second, the numerical results are used for the conception of an active substrate mode spectral filter built from electro-optic zinc oxide. [less ▲]

Non-linear optical measurements and crystalline characterization of CdTe nanoparticles produces by thes electropulse technique

in New Journal of Physics (2004), 6(32),

We propose to extend the ‘electropulse’ technique to synthesize CdTe nanoparticles for optical components. To do so, we create nuclei of the expected material on a titanium electrode immersed in an ... [more ▼]

We propose to extend the ‘electropulse’ technique to synthesize CdTe nanoparticles for optical components. To do so, we create nuclei of the expected material on a titanium electrode immersed in an electrolytic solution by using an electrochemical pulse. The nanoparticles are expelled from the titanium horn surface by cavitation bubbles, which are produced in the solution by a high intensity ultrasound pulse generated by a piezoelectric crystal. Optical absorption spectra and third-order non-linear optical properties of a colloidal solution of CdTe particles produced by this technique are presented. The non-linear refractive index was characterized using the single-beam z-scan technique, and measurements were carried out at several incidence intensities. Non-linear indices of refraction between −1.2×10−7 and −2×10−8 cm2W−1 were measured. [less ▲]

Le Projet OSIRIS (Optical Systems for Interferometric Relief Investigation and Scanning). Projet de développement d'un système de relevé numérique des documents archéologiques en trois dimensions par des procédés optoélectroniques

in L'archéométrie au service des monuments et des livres d'art (2003)

Customization of a self-processing polymer for obtaining specific diffractive optical elements

in Synthetic Metals (2002), 127

Photopolymerizable materials are capable of recording volume holograms via a change in refractivity of the layer. On illumination by an interference pattern around 500 nm, polymerization and diffusion led ... [more ▼]

Photopolymerizable materials are capable of recording volume holograms via a change in refractivity of the layer. On illumination by an interference pattern around 500 nm, polymerization and diffusion led to regions with various segment densities. A modulation of the refractive index took place, thus giving rise to permanent thick phase gratings created in situ in the emulsion. This modulation was estimated at 7 x 10(-3), corresponding to diffraction efficiencies of ca. 80% for transmission holography. Applications for the fabrication of diffractive optical elements can be expected in view of the experimental results and the simplicity of use. For instance, the duplication of computer-generated holograms on a photopolymerizable film led to thick phase holograms with higher diffraction efficiencies. Substrate-mode polarizing elements were also produced, taking advantage of the laminated property since this emulsion was embedded between two glass plates. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

The OSIRIS Project (Optical Systems for Interferometric-Photogrammetric Relief Investigation and scanning), Development of a device for 3D numerical recording of archaeological and epigraphic documents by optoelectronic processes

in Proceedings of the CIPA WG6 international workshop on Scanning for Cultural Heritage Recording (2002)