Spectral hole burning in thulium-doped glass ceramics (original) (raw)
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Distribution of thulium in Tm3+-doped oxyfluoride glasses and glass-ceramics
CrystEngComm, 2013
Rare-earth (RE) doped transparent glass-ceramics are presented as very promising materials for optical applications. In this work, Transmission Electron Microscopy techniques have been used to structurally characterize a glass of composition 55SiO 2 -20Al 2 O 3 -15Na 2 O-10LaF 3 (mol%), doped with 1 mol% Tm 2 O 3 , and the corresponding glass-ceramic. The proposed crystallization mechanism for this glass has been modified from the results obtained through advanced STEM/EDXS techniques. The parent glass contains phase separated regions mainly enriched in F and La and also in Al, Si and Tm. After annealing, 10-20 nm LaF 3 nano-crystals are formed from these phase separated droplets. The partial incorporation of the doping Tm 3+ ions into the LaF 3 nano-crystals has been verified and the interphase crystal/glassy matrix has been more precisely characterized through EDXS. An Al enriched layer is formed around the crystals followed by a Si enriched shell, which greatly increase the viscosity in the periphery of the crystals, inhibiting further crystal growth and thus, keeping the nano size of the crystals.
Tm3+ doped oxy-fluoride glass-ceramics containing NaLaF4 nano-crystals
Optical Materials, 2010
Oxy-fluoride glass-ceramics offer a promising alternative as hosting of lanthanide ions, making them suitable for the fabrication of optical devices. In this study, transparent oxy-fluoride glass-ceramics doped with Tm 3+ have been obtained from glasses in the system K 2 O-Na 2 O-Al 2 O 3-SiO 2-LaF 3 by heat treatments slightly above the glass transition temperature, T g. Under that treatment, NaLaF 4 nano-crystals with sizes up to 30 nm precipitate. The crystallisation has been studied as a function of the heat treatment by using dilatometry, X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The distribution of Tm 3+ between glassy matrix and fluoride nano-crystals has been analysed from photoluminescence spectra.
Tm 3+-activated transparent oxyfluoride glass–ceramics: structural and spectroscopic properties
Journal of Non-crystalline Solids, 2004
Ultra-transparent glass–ceramics activated with thulium ions were fabricated employing different heat treatments of precursor oxy-fluoride glass. The spectroscopic properties of the thulium ions, studied through UV–Vis–NIR absorption and luminescence spectroscopy, showed that most of the active ions were embedded in the crystalline phase. The size of nucleated nanocrystals, controlled by the temperature and time of annealing and measured by low-frequency-Raman spectroscopy, was found to range from 7 to 18 nm. From the absorption measurement we extracted the cross-sections of Tm3+ ions embedded in the crystalline and glassy phases. Judd–Ofelt analysis was carried out on precursor glass and crystal. Comparing calculated and experimental lifetimes, before and after the heat treatment procedure, we found that the ceramming increases the quantum efficiency of the Tm3+ electronic transitions.
Journal of Applied Physics, 2006
The doping distribution of Tm 3+ ions in a transparent oxyfluoride glass ceramic has been investigated. Optical absorption, luminescence, and excitation measurements have been performed in order to determine the environment in which Tm 3+ ions and the infrared emissions they give rise to are located. An interesting result has been found: the main contribution to the 1465 nm emission ͑S band͒ is due to Tm 3+ ions in the crystalline phase for low doping level. However, when the Tm 3+ concentration is high the S-band emission comes from the small portion of Tm 3+ that remains in the vitreous phase. It has been concluded that cross relaxation ͑CR͒ processes are responsible for the quenching of the S-band emission in the crystalline phase for high doping concentration. Lifetime measurements of the 3 H 4 level have also been taken and the probability of CR processes deduced.
Journal of Alloys and Compounds, 2001
Effect of activator concentration on luminescence spectra and luminescence decay of excited states of Tm in indium-based fluoride 1 1 3 glass has been investigated. Self-quenching of luminescence originating in the D , G and the H levels is found to be significant at 2 4 4 doping levels as low as 0.5%. Luminescence decay curves are consistent with the Inokuti-Hirayama model for the non-radiative energy 1 transfer involving an electric dipole-electric dipole interaction. Critical distance R 512.3 A, derived from an analysis of the G decay, is 0 4 relatively high and indicates that the glass matrix favours the ion-ion interaction. Relaxation dynamics for glass samples doubly doped 3 with thulium and terbium provides evidence that terbium ions are able to shorten the F lifetime with extremely high efficiency. 4 31 31 3 However, the Tm →Tb energy transfer contributes adversely to relaxation of the H level. Critical distance for this interaction is 4 31 nearly the same as that for the self-quenching of Tm luminescence.
Journal of the American Ceramic Society, 2012
The influence of the addition of 1 mol% Tm 2 O 3 on the nanocrystallization of LaF 3 in a glass of composition 55SiO 2 -20Al 2 O 3 -15Na 2 O-10LaF 3 (mol%) has been studied. Tm 2 O 3 affects the phase separation in the glass and delays the onset of crystallization with respect to the undoped glass. Additionally, the maximum LaF 3 crystal size is slightly greater than that in the undoped glass-ceramics. The microstructural and compositional changes in the glass matrix have been studied using several techniques, including viscosity, dilatometry, X-ray and neutron diffraction (XRD, ND), quantitative Rietveld refinement, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and Raman spectroscopy. Photoluminescence measurements indicate that the Tm 3+ ions are distributed between the glassy matrix and LaF 3 crystals. Eu 2 O 3 has been used as structure probe and part of the Eu 3+ ions are reduced to Eu 2+ when incorporated in the LaF 3 nanocrystals. Up-conversion spectra under IR-excitation show a higher intensity of the blue emission in the Tm-doped glassceramic compared with that in the glass.
Site-resolved emission of Nd3+-doped oxyfluoride nano glass-ceramics
Optical Components and Materials XV, 2018
Transparent oxyfluoride glass-ceramics obtained by the adequate heat treatment of Nd 3+-doped glass with composition SiO 2-Al 2 O 3-Na 2 O-LaF 3 are investigated. X-ray diffraction (XRD) and high resolution transmission electron microscopy (HR-TEM) show that the precipitated nanocrystals are LaF 3 with a crystal size between 9-12 nm. Furthermore, energy dispersive X-ray (EDX) analysis shows the incorporation of Nd 3+ ions into the LaF 3 nanocrystals. Site-selective and time-resolved emission and excitation spectra of the 4 F 3/2 and 4 F 5/2 states, allows to unambiguously isolate the emission of Nd 3+ ions in LaF 3 nanocrystals which shows well defined spectra, similar to those obtained for pure LaF 3 crystal.
Journal of Non-Crystalline Solids, 2014
Incorporation of rare-earth (RE) ions in the fluoride crystals of oxyfluoride glass-ceramics greatly improves the optical properties of these materials, such as the up-conversion emission. In this work, we present a study of this incorporation using X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. Both techniques allow quantifying the distribution of these ions in the glass matrix and the fluoride crystals. We found that 27% of Tm 3+ ions are incorporated in LaF 3 nano-crystals.
Journal of Applied Physics, 2010
95SiO 2 -5LaF 3 sol-gel derived nano-glass-ceramics single doped with 0.1Dy 3+ or 0.1Tb 3+ mol % and codoped with 0.1Dy 3+ and xTb 3+ ͑x = 0.1, 0.3͒ mol % were successfully obtained. XRD and HRTEM measurements confirm the precipitation of LaF 3 nanocrystals during the ceramming process, with mean size ranging from 10 to 20 nm and increasing with the thermal treatment temperature. About 75% of lanthanide ions are partitioned into LaF 3 nanocrystals, as calculated from luminescence decays. The effect of increasing the Tb 3+ concentration and also of codoping with Dy 3+ in the Tb 3+ green emission from the 5 D 4 level have been studied. The energy transfer mechanisms between Tb 3+ ions and also between Tb 3+ -Dy 3+ ions, which favor the green emission, have been analyzed.
International Journal of Applied Glass Science, 2015
Transparent glass-ceramics containing Er 3+-doped sodium lutetium fluoride nanocrystals for photonic applications have been synthesized. Glass transition temperature, softening temperature, and crystallization temperature were estimated by dilatometry and differential thermal analysis. Proper heat treatments were selected to crystallize lutetium fluoride nanocrystals. X-ray diffraction analysis was carried out to identify the crystalline phase and the crystal size. HRTEM indicates that the base glass is phase separated in droplets enriched in Lu, Na, F, and also Er ions. The thermal treatment induces the crystallization