Three-Dimensional Laser Creation of a Near-IR Laser-Gain Medium Based on Hydride Donor/Acceptor Complexes Made of Coupled Laser-Induced Silver Nanoclusters with Ytterbium Ions.

Femtosecond laser inscription in a ytterbium-doped silver-containing phosphate glass is demonstrated by achieving 3D highly localized laser-induced silver photochemistry. The produced fluorescent silver nanoclusters lead to high optical contrast in the visible range, showing that the coinsertion of Yb ions is not detrimental to the silver-based photochemistry. We demonstrate efficient energy transfer from these silver nanoclusters to the rare-earth Yb ions, leading to near-IR background-free fluorescence emission.

Optical and structural characterization of femtosecond laser written micro-structures in germanate glass.

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.

Toward low-loss mid-infrared GaO-BaO-GeO optical fibers.

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, their development is rather cumbersome due to either poor crystallization and hygroscopicity resilience or poor mechanical-thermal properties of the FCGs.

Spatial beam reshaping and large-band nonlinear conversion in rectangular-core phosphate glass fibers.

Here we present the ability of Nd-doped zinc-phosphate glasses to be shaped into rectangular core fibers. At first, the physico-chemical properties of the developed PO-based materials are investigated for different concentrations of neodymium oxide and core and cladding glass compositions are selected for further fiber development. A modified stack-and-draw technique is used to produce multimode large rectangular-core optical fibers.

Thermal History Mapping in Powder Bed Laser Sintering at the Micrometer Scale.

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

Chemistry Platform for the Ultrafast Continuous Synthesis of High-Quality III-V Quantum Dots.

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 temperature (5 K), confirming their high quality.

Transparent Glasses and Glass-Ceramics in the Ternary System TeO-NbO-PbF.

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

Radiation-Induced Defects and Effects in Germanate and Tellurite Glasses.

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 nonlinear optical properties. Here, we summarize information about possible radiation-induced defects, mechanisms of their formation, and the influence of the glass composition on this process.

Optical Emission Detector Based on Plasma Discharge Generation at the Tip of a Multimaterial Fiber.

Experimental development of a compact optical emission detector based on the assembly of a polymer-metal and a standard silica fiber is presented in this paper. This device is exploited in a proof-of-principle experiment for gas detection application by means of plasma spectroscopy in the visible-Near Infrared spectral region. A multimode fiber (MMF) is associated with a functional hollow dual-electrodes elongated structure fabricated by the direct preform-to-fiber homothetic co-drawing.

Direct laser writing of a new type of waveguides in silver containing glasses.

Direct laser writing in glasses is a growing field of research in photonics since it provides a robust and efficient way to directly address 3D material structuring. Generally, direct laser writing in glasses induces physical modifications such as refractive index changes that have been classified under three different types (Type I, II & III). In a silver-containing zinc phosphate glass, direct laser writing additionally proceeds via the formation of silver clusters at the periphery of the interaction voxel.

Sub-diffraction-limited fluorescent patterns by tightly focusing polarized femtosecond vortex beams in a silver-containing glass.

We report that the shape and size of fluorescent patterns can be controlled by the focused laser intensity distribution, which depends on irradiation conditions as well as on the spin and orbital angular momenta being carried by light, inducing the formation of silver cluster patterns in a silver-containing zinc phosphate glass. In particular, we demonstrate that sub-diffraction-limited inner structures of fluorescent patterns can be generated by direct laser writing (DLW) with tightly focused femtosecond laser vortex beams as Laguerre-Gauss modes (LG0l) with linear and left-handed circular polarizations. We believe this technique, further combined with dual-color DLW, can be useful and powerful for developing structured light enabled nanostructures.

Dual-color control and inhibition of direct laser writing in silver-containing phosphate glasses.

We report on dual-color control of femtosecond direct laser writing (DLW) in a noncommercial silver-containing zinc phosphate glass, thanks to an additional illumination with a cw (continuous wave) UV laser, either after the femtosecond irradiation or simultaneously. By tuning the cw UV power, we demonstrate the tunable control and inhibition of the production efficiency of laser-induced fluorescent silver clusters, leading up to 100% inhibition for simultaneous co-illumination when the laser writing is performed close enough to the permanent structuring threshold. The role of the cw UV illumination is discussed in terms of inhibition of the silver cluster precursors or of dissolution of the laser-induced silver clusters.

Patterning linear and nonlinear optical properties of photosensitive glasses by femtosecond structured light.

We report on structured light-induced femtosecond direct laser writing (DLW) under tight focusing in non-commercial silver-containing zinc phosphate glass, which leads to original patterns of fluorescent silver clusters. These fluorescence topologies show unique features of frustrated diffusion of charged species, giving rise to distorted silver cluster spatial distributions. Fluorescence and second harmonic generation correlative microscopy demonstrate the realization of structured light-induced direct laser poling, resulting from a laser-induced permanent and stable electric field buried inside the modified glass.

Enhancement of nanograting formation assisted by silver ions in a sodium gallophosphate glass.

We investigated the influence of silver ions during the direct femtosecond laser-induced formation of nanogratings (NGs) at the surface of a tailored sodium gallophosphate glass. We observed that the silver ions had a remarkable influence because the silver-containing glass showed (1) lower fluence thresholds for the formation of the NGs; (2) much smoother NG shapes; and (3) a bifunctional behavior because fluorescence from laser-induced silver clusters occurs prior to the formation of the NGs. We demonstrate for the first time, to our knowledge, the formation of NGs assisted by noble metal ions, such as ions playing a kind of catalytic-like role that enhances and improves the NG formation and its incubation process.

Examination of femtosecond laser matter interaction in multipulse regime for surface nanopatterning of vitreous substrates.

The paper presents our results on laser micro- and nanostructuring of sodium aluminosilicate glass for the permanent storage purposes and photonics applications. Surface structuring is realized by fs laser irradiation followed by the subsequent etching in a potassium hydroxide (10M@80 °C) for 1 to 10 minutes. As the energy deposited is lower than the damage and/or ablation threshold, the chemical etching permits to produce small craters in the laser modified region.

Three-dimensional direct femtosecond laser writing of second-order nonlinearities in glass.

We demonstrate that direct femtosecond laser writing in silver-containing zinc and gallium phosphate glass enables generation of three-dimensional (3D) optical second-order nonlinear microstructures having an χ(2) value about 2.5 times that of quartz. The proposed physical model involves photo-reduction, photo-dissociation, and migration of silver species within the glass matrix.

Emission-photoactivity cross-processing of mesoporous interfacial charge transfer in Eu3+ doped titania.

Periodic mesoporous Eu(3+) doped titania materials were obtained through the EISA (Evaporation Induced Self Assembly) process. Eu(3+) ions, entrapped within the semi-crystalline walls of the highly porous framework, appear to be advantageous during the probing of surface photochemical reactions. Its emission intensity is very sensitive to the presence of physisorbed molecules, in gas or liquid phase, that reside within the pores.

Synthesis and characterization of Eu, Ti @ ZnO organosols and nanocrystalline c-ZnTiO thin films aiming at high transparency and luminescence.

By exploiting colloidal properties, such as transparency, rheology and versatile chemistry, we propose to synthesize new photonic nanomaterials based on colloidal solutions and thin films. This contribution highlights our efforts to elaborate and to characterize nanostructures based on the ZnO-TiO system. Using a recently developed sol-gel route to synthesize new Ti@ZnO organosols, we were able to prepare, at relatively low temperature (400 °C) and short annealing time (15 min), highly transparent, luminescent, nanocrystalline Eu doped c-ZnTiO thin films.

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.

Europium-doped mesoporous titania thin films: rare-earth locations and emission fluctuations under illumination.

Herein, Eu(III)-doped 3D mesoscopically ordered arrays of mesoporous and nanocrystalline titania are prepared and studied. The rare-earth-doped titania thin films-synthesized via evaporation-induced self-assembly (EISA)-are characterized by using environmental ellipsoporosimetry, electronic microscopy (i.e.

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.