A. Miguel

Spectral study of the stimulated emission of Nd 3+ in fluorotellurite bulk glass

In this work we present, for the first time to our knowledge, laser emission under wavelength selective laser-pulsed pumping in Nd(3+)-doped TeO(2)-ZnO-ZnF(2) bulk glass for two different Nd(3+) concentrations. The fluorescence properties of Nd(3+) ions in this matrix which include, Judd-Ofelt calculation, stimulated emission cross-section of the laser transition and lifetimes are also presented. The site-selective emission and excitation spectra along the (4)I(9/2)→(4)F(3/2) absorption band show the inhomogeneous behaviour of the crystal field felt by Nd(3+) ions in this fluorotellurite glass which allows for spectral tuning of the laser output pulse as a function of the pumping wavelength. The emission cross-section obtained from the Judd-Ofelt analysis and spectral data (4.9x10(-20) cm(2)) is in fairly good agreement with the value obtained from the analysis of the laser threshold data (4x10(-20) cm(2)).

Active Mid-IR emissions from rare-earth doped tellurite glass ceramics for bio applications

Intense emission peaking at 2.18 μm was successfully obtained from erbium upon carefully designed engineering of its glass host both thermally and spectroscopically. Highly localized crystallization of erbium sites is verified by micro Raman and micro-PL along with TEM characterizations.

Luminescence properties of Er 3+ ions in nanocrystalline glass-ceramics

In this work, we analyze the influence of the nanocrystallization process on the luminescence properties of Er3+ ions in transparent oxyfluoride tellurite glass-ceramics obtained by heat treatment of the precursor Er-doped glass. The comparison between the fluorescence properties of Er-doped glass and glass-ceramics suggests that a fraction of Er3+ ions are forming nanocrystals while the rest remain in a glass environment. The presence of fluoride nanocrystals has a strong effect in the upconverted red emission from 4F9/2 level. This emission increases significantly as compared with the green one in the glass-ceramic sample. The time evolution of the upconverted red emission shows that energy transfer upconversion processes are responsible for the increase of this emission in the glass-ceramic samples.

Photoluminescence emission in Er-activated good quality fluorotellurite thin film glasses

Summary form only given. New applications of optical communications technologies, such as high-density WDM schemes require functional integrated optical circuits allowing operation in the whole range of the telecommunication window (1.2-1.7 μm). However, Er-doped silica still constitutes the backbone of current technologies due to the characteristics of the <;sup>4<;/sup>I<;sub>13/2<;/sub>→<;sup>4<;/sup>I<;sub>15/2<;/sub> emission transition of Er<;sup>3+<;/sup> ions at 1.5 μm. Yet, this need has generated a large effort to find materials able to satisfy these requirements. Fluorotellurite glasses are particularly attractive for the development of integrated gain media since they combine the good optical properties of fluorides (a broad transparency range, low optical losses, and low phonon energies) with the better chemical and thermal stability of tellurite glasses. Moreover, they show high rare-earth (RE) ion solubility and present a variety of sites for the RE-ions, all of which broaden the photoluminescence (PL) bandwidth and enhance the radiative emission [1,2]. However, the production of good quality thin film RE-doped fluorotellurite glasses still constitutes a challenge [3].In our experiments we exploit the advantages of pulsed laser deposition (PLD) in the case materials having complex stoichiometry [4], to produce Er-doped fluorotellurite (TeO2-ZnO-ZnF2) thin film glasses. Transparent films were synthesized at room temperature in an oxygen pressure. Structural characterization of the deposited films shows a similar structure than the parent bulk glass, although they resulted enriched in oxygen and with a small reduction of fluorine content. Optical characterization shows that film glasses present large linear refractive index (nm 1.95 @ 1.53 μm) with reduced absorption (k <;0.01), while their transmission is similar to that of the parent bulk glass (Tm 80 % in the 0.5-2.0 μm range).Absorption and emission PL spectra and lifetimes have been measured in the visible and infrared regions. Figure 1.a compares the room temperature normalized PL spectra corresponding to the 4I13/2-4I15/2 transition of Er3+ ions measured for thin films annealed at 310 °C and for the parent bulk glass. As can be seen form the figure both spectra are similar although a slight decrease of the emission shoulders at 1.50 and 1.55 μm is observed in the case of the film glasses. It is also noticeable that thin film glasses show a large increase of the PL intensity at 1.53 μm upon annealing at temperatures close to 300 °C (Figure 1.b). The evolution of the PL intensity and lifetime upon annealing will be discussed in terms of the effect of annealing on the glass structure and the probability of nonradiative energy transfer between Er3+ ions.