44 research outputs found
Temporal dynamics of IR-to-visible up-conversion in LiNbO3:Er3+/Yb3+: a path to phosphors with tunable chromaticity
This paper was published in Optical Materials Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OME.2.001529. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under la
Micro-Raman characterization of Zn-diffused channel waveguides in Tm3+: LiNbO3
This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OE.18.005449. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under la
Single polarized Tm3+ laser in Zn-diffused LiNbO3 channel waveguides
Copyright (2005) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 86 (2005): 161119 and may be found at http://apl.aip.org
Red, green, and blue simultaneous generation in aperiodically poled Zn-diffused LiNbO3:Er3+/Yb3+ nonlinear channel waveguides
Copyright (2003) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Applied Physics Letters 83.15 (2003): 2991-2993 and may be found at http://apl.aip.org
LaPO4:Er microspheres with high NIR luminescent quantum yield
Er-doped LaPO4 microspheres have been synthesized by spray pyrolysis and the near infrared (NIR) properties have been characterized. It has been found that, following an adequate post-annealing treatment, the emission properties are remarkably improved. The NIR luminescence intensity is highly enhanced and its decay time increases to a value almost coincident with the reported radiative lifetime, which implies that the quantum yield approaches η ≈ 100%. This improvement in luminescence characteristics is probably related to the suppression of residual OH- radicals, that otherwise act as NIR luminescence quenchers, and to the increase in material's crystallinityJunta de Andalucía FQM6090Madrid Ministerio de Ciencia e Innovación CRONOSOMATS MAT2009-14102 MICROSERES-CM P2009/TIC-147
The luminescent quantum efficiency of Cr³⁺ ions in co-doped crystals of LiNb0<syb>3</sub> : ZnO determined by simultaneous multiple-wavelength photoacoustic and luminescence experiments
In this paper, the luminescent quantum efficiency of Cr³⁺ ions in co-doped crystals of LiNb03: ZnO: Cr³⁺ is determined by using a method based on simultaneous multiple-wavelength measurement of photoacoustic and luminescence signal after pulsed laser excitation. The quantum efficiency found in this lattice was (10 ±4)% . This result was compared with the value found from the study of the lifetime in terms of the temperature of the luminescent levels involved. In this last case, two non-equivalent crystal sites were found for Cr³⁺ ions, and two fluorescence quantum yields were determined. After the estimation of the concentration of each site by electron paramagnetic resonance experiments, the averaged fluorescence quantum yield value was (9 ± 2)% in agreement with the previous result.Facultad de Ciencias ExactasCentro de Investigaciones Óptica
The luminescent quantum efficiency of Cr³⁺ ions in co-doped crystals of LiNb0<syb>3</sub> : ZnO determined by simultaneous multiple-wavelength photoacoustic and luminescence experiments
In this paper, the luminescent quantum efficiency of Cr³⁺ ions in co-doped crystals of LiNb03: ZnO: Cr³⁺ is determined by using a method based on simultaneous multiple-wavelength measurement of photoacoustic and luminescence signal after pulsed laser excitation. The quantum efficiency found in this lattice was (10 ±4)% . This result was compared with the value found from the study of the lifetime in terms of the temperature of the luminescent levels involved. In this last case, two non-equivalent crystal sites were found for Cr³⁺ ions, and two fluorescence quantum yields were determined. After the estimation of the concentration of each site by electron paramagnetic resonance experiments, the averaged fluorescence quantum yield value was (9 ± 2)% in agreement with the previous result.Facultad de Ciencias ExactasCentro de Investigaciones Óptica
Crystal structure, NIR luminescence and X-ray computed tomography of Nd3+:Ba0.3Lu0.7F2.7 nanospheres
Uniform, hydrophilic 50 nm diameter Nd3+-doped Ba0.3Lu0.7F2.7 nanospheres are synthesized at 120 °C using a singular one-pot method based on the use of ethylene glycol as solvent, in the absence of any additive. The composition and crystal structure of the undoped material are analyzed in detail using ICP and XRD, which reveals a BaF2 cubic crystal structure that is able to incorporate 70 mol% of Lu ions. This finding contrasts with the reported phase diagram of the system, where the maximum solubility is around 30 mol% Lu. XRD proves as well that the Ba0.3Lu0.7F2.7 structure is able to incorporate Nd3+ ions up to, at least 10 mol%, without altering the uniform particles morphology. The Nd-doped particles exhibit nearinfrared luminescence when excited at 810 nm. The maximum emission intensity with the minimum concentration quenching effect is obtained at 1.5% Nd doping level. X-ray computed tomography experiments are carried out on powder samples of the latter composition. The sample significantly absorbs X-ray photons, thus demonstrating that the Nd3+-doped Ba0.3Lu0.7F2.7 nanospheres are good candidates as contrast agents in computed tomography.Ministerio de Economía y Competitividad MAT2014-54852-R, MAT2012-34919Consejo Superior de Investigaciones Científicas 201560E056, 201460E00
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Spectroscopic characterization of Er3+-doped CaF2 nanoparticles: Luminescence concentration quenching, radiation trapping and transition probabilities
Er3+-doped CaF2 nanoparticles (NPs) with variable dopant concentration were synthesized by a direct precipitation method. X-Ray Powder Diffraction, SEM and TEM were used to analize the crystalline structure and morphology. The spectroscopic characterization, as function of the Er3+ content, has been performed under CW and pulsed excitation. Under steady state conditions, it has been found that the intensity of the main emission bands is affected by luminescence quenching processes. The population dynamics, recorded under pulsed excitation, confirms not only the existence of quenching processes but also the occurrence of radiation trapping. The intrinsic transition probabilities of the main Er3+ emitting manifolds, in absence of quenching and radiation trapping, have been estimated through a procedure commonly used in bulk doped materials. A modified Judd-Ofelt analysis has been performed to determine the radiative transition probabilities, radiative lifetimes and branching ratios of the Er3+ levels. Finally, an estimation of the gap law in these NPs is givenThis work has been partially supported by Ministerio de Ciencia e
Innovación (Spain) under project COLUMNAS
(PID2019–110632RB-I00