Thierry Cardinal

CNRS - University of Bordeaux · ICMCB

Ionizing irradiation was performed on barium–germanium–gallium (BGG) glasses using a 2.5 MeV electron beam. Through electron spin resonance spectroscopy, paramagnetic point defects, such as germanium- and gallium-related electron and hole trap centers, have been identified. The presence of silver in the BGG glass appears to hinder the stability of...

Localized sub-micrometer-scale visible and near-IR fluorescence structures have been achieved in threedimension (3D) thanks to femtosecond laser-activated photochemistry of Bismuth in a Bismuth-doped phosphate glass. These structures exhibit high fluorescence contrast with good spatial resolution with spectral emission in the red and near-IR ranges...

Borogermanate glasses containing terbium ions are interesting materials due to their luminescent and magnetic properties. Terbium can present two different oxidation states and the thermal poling technique can be a pertinent way to modulate spatially the oxidation state of these ions. In this work, we demonstrate using a thermo-electrical imprintin...

A thermo-electrical imprinting process on a borogermanate glass containing Tb ³⁺ have permitted a micrometric structuring of the oxidation state of Tb ions. Correlative luminescence, Raman and SHG microscopies demonstrate modification of the glass structure accompanying large luminescence changes and the appearance of an electro optical response.

Two barium gallo-germanate glass series were elaborated to investigate the effect of the yttrium introduction on the glass physicochemical properties and crystallization behavior. One to twenty mol% of YO3/2 were either added into the glass matrix or substituted for gallium oxide. The glass structure was studied by Raman spectroscopy and the therma...

Since the development of the first fibroscope in the late nineteenth century, the use of innovating glass fibers has opened promising perspectives for medical applications particularly in the domain of multimodal imagery[1]. In this work, tellurite glasses have been used to design step-index optical fibers with a rectangular core-section for superc...

Monitoring local luminescence properties in 3D multi-scale architecture having sub-wavelength dimensions is attractive for multiple potential applications for sensors, optical data storage, integrated light source, or data communication. For such a challenge, Femtosecond (fs) Direct Laser Writing (DLW) stands out as an unique technique to imprint i...

A novel type of waveguide Bragg grating (WBG) is demonstrated based on femtosecond laser-induced Type A refractive index modifications, namely based of the photochemistry of silver species in a specialty ortho-phosphate glass matrix. First-order WBGs are reported in the near-infrared and down to 736 nm in the visible. Relative transmission measurem...

We report on direct femtosecond laser writing in zinc barium gallo-germanate glasses. A combination of spectroscopic techniques allows to progress in the understanding of the mechanisms taking place depending on the energy. In the first regime (type I, isotropic local index change) up to 0.5 µJ, the main occurrence is the generation of charge traps...

Gallium‐rich heavy metal oxide glasses have become highly attractive optical materials since they exhibit a wide transparency window spanning from the ultraviolet ∼270 nm up to the mid‐infrared (IR) region ∼6 μm making them promising for a future integration in optical fiber devices. Nonetheless, in most composition, surface crystallization is a ke...

The femtosecond direct laser writing technique provides a robust and efficient way to directly inscribe embedded 3D photonic devices in bulk glasses. Following direct laser writing, a local optical properties change is induced that is generally classified under three distinguished types (type I, type II, and type III). Each type allows for the fabr...

The development of efficient and compact photonic systems in support of mid-infrared integrated optics is currently facing several challenges. To date, most mid-infrared glass-based devices are employing fluoride or chalcogenide glasses (FCGs). Although the commercialization of FCGs-based optical devices has rapidly grown during the last decade, th...

Thermal poling using microstructured electrodes on oxyfluoride glasses have been investigated and the impact on optical properties was evaluated. A micrometer refractive index modification based on the sodium and fluorine migration has been evidenced, through the creation of a layer with different chemical composition as compared to the original gl...

Si le verre possède de nombreux atouts, ses propriétés optiques sont parmi les plus remarquables. Sa transparence et son indice de réfraction ont longtemps été reliés exclusivement à sa composition globale. Cependant, la structuration des propriétés optiques en surface ou au coeur du verre, à l’échelle micro ou nanométrique, connait un engouement p...

In the present work, the effect of electron irradiations on silver-containing phosphate glasses using a 2.5 MeV electron beam has been explored by Electron Spin Resonance (ESR) and luminescence spectroscopy. The process involved in the interaction of electron beam with both the silver-containing and silver-free phosphate glass matrix and the format...

Herein, a tellurite multimode optical fiber with a rectangular step‐index core to combine easy coupling of the pump power with the exceptionally cubic nonlinearity of such type of glass is developed. An alkali‐free composition (TeO2–ZnO–La2O3) is prepared to produce a preform with the use of both the stack‐and‐draw and the direct‐bonding methods. T...

A thermal sensor was used to better understand parameters which influenced the interaction between a laser beam and a 0.5% Mn-doped ZnAl2.2O4 material, especially the laser defocusing parameter. The optical properties of the material depend on whether the Mn2+ ions occupy octahedral and/or tetrahedral sites depending on thermal history. A screen pr...

We report the fluorescent properties of 3D localized structure with size near the diffraction limit induced by femtosecond direct laser writing (DLW) in Yb³⁺ and silver-containing phosphate glass. The homogenous dispersion of the silver ions and Yb³⁺ ions in the glass matrix before DLW was evidenced using photo-luminescent spectroscopy and time-res...

Here we explore the manufacturing of niobium-rich borophosphate glasses into fibers with optical quality. Glass preforms of composition [(100-x) (0.95 NaPO3 + 0.05 Na2B4O7) - x Nb2O5] with x = 37, 38, 39, 40 were synthetized and thermally drawn. Viscosity measurements performed in the softening point range show that the optical fiber drawing temper...

A series of new transparent and magnetic barium gallogermanate glasses in the system (x) Gd2O3 – (100-x) [20BaO−15Ga2O3−65GeO2] with x = 0, 8, 14, 18, 22 and 25 mol% were synthesized. Their thermal, structural and magnetic properties were characterized. Based on the differential scanning calorimetry results, one determined the composition domain ex...

This work demonstrates for the first time the formation of nanogratings inside Barium Gallo-Germanate glasses using femtosecond laser direct writing. These heavy oxide glasses, with a characterized transparency window up to 6 μm, along with the polarization sensitive birefringent nanostructures induced by femtosecond laser, offer an excellent platf...

The direct laser writing (DLW) using femtosecond lasers allows for the inscription of 3D microstructures embedded inside optical materials. Based solely on the silver ions photochemistry, the DLW in silver‐containing glasses enables to locally induce inside glasses a unique combination of optical properties. The physical modifications of the materi...

We report on the synthesis of transparent amorphous hydrated phosphate materials at low temperatures (as low as 300 °C) in the [50 P2O5 – (25 - x/2) K2O – (25 - x/2) Na2O – x ZnO] – n H2O (x = 0 – 25 mol%). These new transparent materials were studied by Raman and FTIR spectroscopies. The structure of the hydrated phosphates is proposed to consist...

Radio-photoluminescence in silver-doped phosphate glasses has been extensively used for X-ray dosimetry. In this paper, we present the potential of silver clusters for X-ray spatially resolved dosimetry. Those clusters are generated in phosphate glasses containing a high concentration of silver oxide by femtosecond direct laser writing technique. T...

Here we report on the effect of potassium or yttrium on the luminescence spectroscopic properties of Yb³⁺-doped germano-gallate glasses as well as the ability to shape them into optical fibers with the objective of using such glasses to produce near-infrared optical gain medium. Two ytterbium-doped germano-gallate glass systems, (100-x) (28Ga2O3 –...

Sodium tantalum germanate glasses were thermally poled using microstructured metallic anodes of two distinct geometries. Topological, structural and optical characterizations of the micro-imprinted structures revealed an accurate reproducibility of the...

Glass forming regions in the system GaO3/2 – GeO2 – LaO3/2 – BaO have been explored using aerodynamic levitation coupled to laser heating synthesis technique. Structure property relationships have been established between the thermal and optical properties of the resulting glass thanks to Raman and Infrared vibrational spectroscopies. The germano-g...

A chemistry platform for the fast continuous synthesis of III–V quantum dots is demonstrated. III‐nitride QDs are prepared by using short residence times (less than 30 s) in a one‐step continuous process with supercritical solvents. GaN QDs prepared via this route exhibit strong UV photoluminescence with a structuring of the emission signal at low...

Barium germano-gallate glasses are attractive glass hosts for photonic applications in the mid-infrared region up to 6 μm. In this work, we investigate the photosensitivity of such glasses under femtosecond laser, with an emphasize on the formation of refractive index changes. Six glasses with varying compositions (including addition of K, Na, Y, a...

Ho³⁺-doped YNbO4 and Y3NbO7 phosphors were synthesised via a co-precipitation synthesis route. Structural characterisation and spectroscopic properties were performed as a function of the Ho³⁺ concentration. The Rietveld type-refinement confirms the stabilisation of the pure monoclinic Fergusonite YNbO4 phase at the highest temperatures, but the qu...

The structure and crystallization of silver-doped germano-gallate glasses for substitution of potassium for barium ions have been investigated. By means of Raman spectroscopy, a structural study has been carried out revealing a glass network depolymerization with the formation of non-bridging oxygens likely localized on germanium tetrahedra when th...

Complex sequential crystallization mechanisms were investigated in the glass composition 70GeO2-10Na2O-20Ta2O5 prepared by melt-quenching. In a first stage, a classical volume-nucleated crystallization of sodium tantalate perovskite Na2Ta8O21 is induced under short time heat-treatments whereas longer annealing treatments promote the formation of su...

Additive manufacturing (AM), especially powder bed laser sintering (PBLS), has been an increasingly popular field since the 1980s. Direct SLS is particularly challenging with ceramic materials due to their low thermal conductivity, high melting point, and brittle mechanical behaviour. In addition, they require longer processing times for a reliable...

The ability to produce robust fiber-based integrated optical systems operating over a wide spectral domain (UV to mid-infrared), is one of today’s key challenges in photonics. This work reports on the production of crystal-free, light guiding fibers from rich Ga2O3 oxide-based glass compositions. These materials show optical transmission extending...

Herein, our attention is focused on the second‐order optical properties of thermally poled sodo‐niobate amorphous thin films through an original methodology that combines both macroscopic and microscopic second harmonic generation techniques. By probing the geometry and the magnitude of the second‐order nonlinear (SONL) optical response at differen...

Here, it is demonstrated that the stack‐and‐draw approach can be expanded to unusual materials association and profile geometries to generate fiber assemblies with unprecedented functionalities. This approach relies on the stacking of flat oxide glass slides into a preform, which is then thermally elongated into tens‐of‐meters‐long ribbon fibers wi...

Volume Bragg Gratings (VBG) are inscribed in the bulk of non-conventional photosensitive glasses tailored with silver by means of femtosecond laser irradiation. Thanks to intrinsic features of the spatial distribution of silver-sustained inscribed structures, it is possible to fabricate gratings with sub-wavelength periodic refractive index modulat...

Implants made of ceramics, and more particularly of calcium phosphates (hydroxyapatite: HA, mainly), promoting intimate contact with natural bone are nowadays merging. Addition of copper ions in bio-ceramics is expected to increase the biological compatibilities of bone graft substitutes. Previous works have shown that copper-doped hydroxyapatite (...

We report on the 3D precipitation, using a direct laser writing approach, of highly fluorescent silver clusters in a Eu3+-doped silver-containing zinc phosphate glass. Micro-spectroscopy of fluorescence emission shows the ability to continuously adjust the local tri-chromatic coordinates in the CIE (Commission Internationale de l’Éclairage) chromat...

Glass-ceramics containing rare earth gallium garnets were obtained using glass compositions as reactional medium. This work reports on the synthesis, and structural, morphological, and optical characterizations of Er³⁺ and Tm³⁺-doped Yb3Ga5O12 crystals prepared from controlled cooling of heavy metal oxide glass melts. Micrometric cubic crystals wer...

Transparent fluorotellurite glasses were prepared by melt-quenching in the ternary system TeO2-Nb2O5-PbF2. The synthesis conditions were adjusted to minimize fluorine loss monitored as HF release. It was found that 10 mol% of Nb2O5 is the optimum content for PbF2 incorporation up to 35 mol% in the tellurite matrix without loss of glass forming abil...

A microstructured SHG pattern on Sm 2 O 3-doped sodium borophosphate niobium (SmBPN) glasses was obtained by laser-induced thermal poling. The optical properties of SmBPN glasses were recorded by UV/Vis/NIR transmission spectra. In situ laser-induced heating of the SmBPN glasses without and with preheating was characterized by an infrared thermal c...

Mn²⁺-doped Zn3(PO4)2 and Mn²⁺-doped ZnAl2·2O4+δ compounds were prepared from solid state route and Pechini process, respectively. The luminescent properties evolution of both as-prepared powder compounds versus the annealing temperature (for 10 min annealing treatments) was studied, in the range 500–1400 °C. In parallel, Doctor Blade was used to pr...

We report for the first time a study on non‐contact thermal poling of soda lime silicate glasses using DC gas discharge. In this work, the formation of a glow discharge is evidenced during the thermal poling treatment (longer than 30 minutes). The hardness and the chemical durability of glasses poled under different conditions (contact or non‐conta...

We examine the thermal drawing of zinc tellurite silver-containing glass. While the silver-doped glass fibers remain unchanged over thermal drawing under oxygenatmosphere, we establish that under argon silver doping leads to the growth of a thin, metallic-like precipitate at the fiber surface. Optical, chemical and structural analysis, supported by...

Additive manufacturing of oxide glass enables on-demand, low-cost manufacturing of complex optical components for numerous applications, opening new opportunities to explore functionalities inaccessible otherwise. Here, we report a straightforward extrusion-based 3D-printing approach, deploying the fused deposition modeling (FDM) process, to produc...

This review focuses on the radiation-induced changes in germanate and tellurite glasses. These glasses have been of great interest due to their remarkable potential for photonics, in terms of extended transmission window in the mid-infrared, ability of rare-earth loading suitable with a laser, and amplification in the near- and mid-infrared or high...

Six niobium rich glasses presenting different sodium contents were synthetized. On the basis of complementary infrared and Raman analysis, the influence of the sodium content and its role on the structure of the glasses prior to and following poling was examined. Correlative second harmonic generation (SHG)/Raman microscopy on the poled glasses cro...

A series of new transparent and magnetic germanoborate glasses in the system (100-x)[60Ge2O3–25B2O3–10Na2O–4Al2O3–1PbO] – (x) Gd2O3, with x = 0, 1, 2, 5, 10, 15 and 20 mol%, was prepared and studied with respect to their thermal and structural changes in the presence of Gd2O3. Based on Differential Scanning Calorimetre (DSC) analysis, a glass with...

WO3-x thin films and WO3-x / Ta2O5 composite films exhibit a huge photochromic effect with 60% of near-infrared transmission modulation, in comparison to literature reviews. The colouring efficiency of such film results from both the stoichiometry of the particles (oxygen/tungsten deficient ratio) and the quality of the films (films are thin, homog...

The design of active optical devices integrating second‐order nonlinear (SONL) optical responses typically relies on the use of dielectric crystalline materials such as lithium niobate (LN) or semiconductors such as GaAs. Despite high SONL susceptibilities, these materials present important geometry constrains inherent to their crystalline nature l...