Thierry Cardinal

Oxyfluoride tellurite glasses doped by erbium: thermal analysis, structural organization and spectral properties

Abstract The effects of fluorine substitution in zinc tellurite glass system doped with rare earths on the spectral properties of the Er 3+ ions are investigated. Differential thermal analysis, vibrational spectroscopies studies and in situ high-temperature X-ray diffraction measurements have been considered in term of fluorine influence. As a function of composition, we have principally measured optical absorption, spontaneous emission, and lifetime measurements. Judd–Ofelt intensity parameters of Er 3+ in these host glasses were determined and used to calculate radiative transition rates and lifetimes. The bulk composition variation and addition of fluoride compounds in tellurite glasses result among others, in broad emission spectra, improved emission lifetime and difference in relative band intensities compared to pure oxide glass.

Silver clusters embedded in glass as a perennial high capacity optical recording medium.

[∗] Dr. A. Royon , Dr. M. Bellec , G. Papon , Dr. B. Bousquet , Prof. L. Canioni Centre de Physique Moleculaire Optique et Hertzienne University of Bordeaux 351 Cours de la Liberation, 33405 Talence (France) E-mail: l.canioni@cpmoh.u-bordeaux1.fr K. Bourhis , Dr. T. Cardinal Institut de Chimie de la Matiere Condensee de Bordeaux University of Bordeaux 87 Avenue du Docteur Schweitzer, 33608 Pessac (France) Dr. Y. Deshayes Laboratoire de l ′ Integration du Materiau au Systeme University of Bordeaux 351 Cours de la Liberation, 33405 Talence (France)

Tellurite glasses with peak absolute Raman gain coefficients up to 30 times that of fused silica.

An experimental system has been assembled to measure the absolute values of the Raman gain spectrum for millimeter-thick glass samples. Results are reported for two new oxide glasses with Raman gain coefficients as much as 30 times larger than that of fused silica and more than twice its spectral coverage.

Photodarkening and photobleaching of an ytterbium-doped silica double-clad LMA fiber

We studied the temporal behaviour of photodarkening in an Yb-doped LMA fiber and show photobleaching of the same fiber. The absorption spectra and the influence on the lasing properties are shown.

Optical non-linearity in oxide glasses

The origin of the optical non-linear response has been investigated in two different types of oxide glasses. Linear and non-linear refractive indices have been obtained by interferometric measurements. Correlations between the local structure of polarizable entities within glasses and their optical activities have been tentatively established through ab initio calculations.

Three-dimensional optical data storage using third-harmonic generation in silver zinc phosphate glass

We demonstrate the possibility of three-dimensional optical data storage inside a specific zinc phosphate glass containing silver by using third-harmonic generation (THG) imaging. Information is stored inside the glass with femtosecond laser irradiation below the refractive index modification threshold. We use the same laser for THG readout. The capability of storage with this technique is discussed.

Correlations between structural properties of Nb2O5NaPO3Na2B4O7 glasses and non-linear optical activities

Abstract Information about the origin of the optical non-linear response in transparent glasses can be gained from a detailed structure investigation using Raman and X-ray absorption spectroscopies. The effects resulting from the introduction of niobium oxide in the sodium borophosphate matrix of composition 0.95NaPO 3 0.05Na 2 B 4 O 7 are described. For small niobium concentrations, the formation of distorted NbO 6 octahedra is observed. The increase of niobium concentration allows the progressive linking of corner-shared and less distorted octahedra. The correlative evolution of the measured third order susceptibilities χ (3) is analyzed on the basis of the bond orbital theory. A good agreement between experimental and calculated χ (3) is obtained as long as the NbO 6 entities are isolated from each other, but the clustering of these entities increases the non-linear response, χ (3) .

Beat the diffraction limit in 3D direct laser writing in photosensitive glass

Three-dimensional (3D) femtosecond laser direct structuring in transparent materials is widely used for photonic applications. However, the structure size is limited by the optical diffraction. Here we report on a direct laser writing technique that produces subwavelength nanostructures independently of the experimental limiting factors. We demonstrate 3D nanostructures of arbitrary patterns with feature sizes down to 80 nm, less than one tenth of the laser processing wavelength. Its ease of implementation for novel nanostructuring, with its accompanying high precision will open new opportunities for the fabrication of nanostructures for plasmonic and photonic devices and for applications in metamaterials.

Highly Transparent BaAl4O7 Polycrystalline Ceramic Obtained by Full Crystallization from Glass

Transparent polycrystalline ceramics are an emerging class of photonic quality materials competing with single crystal technology for a diverse range of applications including high-energy lasers, scintillating devices, optical lenses, and transparent armour. Polycrystalline ceramics offer several advantages, particularly in the fabrication of complex shapes and large-scale industrial production, and enable greater and more homogenous doping of optically active ions than is possible in single crystals. A limited number of either cubic or nanocrystalline transparent polycrystalline ceramics are known, but require complex and time-consuming synthetic approaches. Here, we show for the fi rst time that fully dense transparent polycrystalline ceramics can be simply obtained by direct and complete crystallization from glass. This is demonstrated for the previously unreported composition, BaAl 4 O 7 , which exhibits two orthorhombic polymorphs with micrometer grain size, both optically transparent in the visible range. This innovative synthetic route to transparent polycrystalline ceramics should facilitate the discovery of new, cost-effective chemical methods for transparent ceramic applications. Conventional optically transparent single crystal materials are widely used in numerous photonic applications. However, these materials face several technological and economical challenges, including a restricted list of appropriate single crystal compounds, limitations on the type and level of chemical doping, and mechanical and manufacturing requirements for large and complex physical shapes. Many of these obstacles can be avoided through the use of ceramic materials, which afford a wider range

Coherent acoustic vibration of metal nanoshells

Using time-resolved pump-probe spectroscopy, we have performed the first investigation of the vibrational modes of gold nanoshells. The fundamental isotropic mode launched by a femtosecond pump pulse manifests itself in a pronounced time-domain modulation of the differential transmission probed at the frequency of nanoshell surface plasmon resonance. The modulation amplitude is significantly stronger, and the period is longer than that in a gold nanoparticle of the same overall size, in agreement with theoretical calculations. This distinct acoustical signature of nanoshells provides a new and efficient method for identifying these versatile nanostructures and for studying their mechanical and structural properties.