Structural Studies of Rare-Earth Doped Phosphate Glasses

1996 ◽  
Vol 455 ◽  
Author(s):  
A. Matic ◽  
L. Börjesson ◽  
A. Wannberg ◽  
R. L. McGreevy

ABSTRACTWe have performed neutron scattering experiments on rare-earth (La, Pr, Ho) doped phosphate glasses around the metaphosphate composition R(PO3)3. Combining the diffraction experiment with Reverse Monte Carlo simulations we obtain a 3-D model of the structure. Our models propose a rare-earth ion environment primarily consisting of oxygens with the average rare earth-oxygen distances; 2.56, 2.51 and 2.40 Å for the La, Pr and Ho samples respectively. We also observe that the rare earth ions are not uniformly distributed. The first R-R shell is on avergae about 3.3 Å to be compared with a value of 7 Å for a uniform distribution of R ions in the structure. From the models we also conclude that a chain like structure of the phosphate network is in agreement with the experiment.

1991 ◽  
Vol 244 ◽  
Author(s):  
L. R. Copeland ◽  
W. A. Reed ◽  
M. R. Shahriari ◽  
T. Iqbal ◽  
P. Hajcak ◽  
...  

ABSTRACTRare earth ions can easily be incorporated into fluoride glasses in moderate to large concentrations and, due to their low phonon energy, these glasses appear to have many advantages over oxide glasses as hosts for rare earth ions used in optical amplifiers and lasers. We have therefore investigated the optical properties of Pr3+, Pr3+/Yb3+ and Pr3+/Yb3+/Lu3+ doped bulk AIF3-based glass samples as a function of rare earth ion concentration. We find that the addition of 2 wt% of Yb increases the fluorescence of Pr3+ at 1.32 μm by a factor of 35 when excited with 488 nm radiation. The fluorescence intensity and excited state lifetimes are found to be comparable to those measured for Pr in a ZBLAN host. Since it has also been demonstrated that optical fibers drawn from AIF3-based glasses exhibit relatively low loss (< 0.05 dB/m) and posses superior chemical durability compared to other fluotide glasses, it is possible that AIF3 glasses may become the fluoride glass of choice for practical fiber laser and amplifier applications.


2004 ◽  
Vol 817 ◽  
Author(s):  
D. Pacifici ◽  
G. Franzò ◽  
F. Iacona ◽  
A. Irrera ◽  
S. Boninelli ◽  
...  

AbstractIn the present paper, we will review our work on rare-earth doped Si nanoclusters. The samples have been obtained by implanting the rare-earth (e.g. Er) in a film containing preformed Si nanocrystals. After the implant, samples have been treated at 900°C for 1h. This annealing temperature is not enough to re-crystallize all of the amorphized Si clusters. However, even if the Si nanoclusters are in the amorphous phase, they can still efficiently transfer the energy to nearby rare-earth ions. We developed a model for the Si nanoclusters-Er system, based on an energy level scheme taking into account the coupling between each Si nanocluster and the neighboring Er ions. By fitting the data, we were able to determine a value of 3×10−15 cm3 s−1 for the Si nanocluster-Er coupling coefficient. Moreover, a strong cooperative up-conversion mechanism between two excited Er ions and characterized by a coefficient of 7×10−17 cm3 s−1, is shown to be active in the system, demonstrating that more than one Er ion can be excited by the same nanocluster. We show that the overall light emission yield of the Er related luminescence can be enhanced by using higher concentrations of very small nanoaggregates. Eventually, electroluminescent devices based on rare-earth doped Si nanoclusters will be demonstrated.


2006 ◽  
Vol 518 ◽  
pp. 173-180
Author(s):  
Philippe Goldner ◽  
Olivier Guillot-Noël

Quantum information uses special properties of quantum systems to manipulate or transmit data. This results in new processes, which are impossible to obtain with classical devices. For example, quantum computing and quantum storage, which are two important fields in quantum information research, aim respectively at performing very fast calculations and at storing quantum states of photons. These two applications could be obtained in solid-state systems using rare earth doped crystals. In this context, the most important property of these materials is the long coherence lifetimes of rare earth ion optical and hyperfine transitions. This allows one to create long-lived superposition states, which is a fundamental requirement for efficient quantum computing and storage. Promising results have already been demonstrated in rare earth doped crystals but it will be difficult to improve them with current materials. In this paper, we discuss the general and specific requirements for rare earth ions and crystals in order to perform quantum computing with a large number of quantum bits as well as all solid-state quantum storage. We also present the properties of a few recently studied crystals: Ho3+:YVO4, Ho3+:LuVO4 (quantum computing) and Tm3+:Y3Al5O12 (quantum storage).


1994 ◽  
Vol 358 ◽  
Author(s):  
A.J. Kenyon ◽  
P.F. Trwoga ◽  
M. Federighi ◽  
C.W. Pitt

ABSTRACTWe report the fabrication of rare-earth doped silicon-rich silica thin films by PECVD. The films exhibit absorption edges in the visible region of the optical spectrum consistent with the presence of silicon microclusters. Weak visible photoluminescence due to silicon microclusters is observed. In addition, strong luminescence from the rare-earth ion is obtained even when excited away from characteristic absorption bands; indeed, the luminescence intensity is largely independent of excitation wavelength below 514 nm. We ascribe this to excitation of silicon microclusters followed by an efficient transfer of energy to the rare-earth ions.The very broad absorption of this material opens up the possibility for flashlamp-pumped optoelectronic devices. In addition, we report the fabrication of silicon-rich silica films by PECVD. We show that the optical properties of these films are consistent with the presence of silicon microclusters and show absorption spectra similar to those of the rare-earth doped silicon-rich silica samples. This supports the hypothesis that the principal absorbing species in the rare-earth doped films is microclustered silicon


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3717
Author(s):  
Jae-Young Jung ◽  
Soung-Soo Yi ◽  
Dong-Hyun Hwang ◽  
Chang-Sik Son

The precursor prepared by co-precipitation method was sintered at various temperatures to synthesize crystalline manganese tungstate (MnWO4). Sintered MnWO4 showed the best crystallinity at a sintering temperature of 800 °C. Rare earth ion (Dysprosium; Dy3+) was added when preparing the precursor to enhance the magnetic and luminescent properties of crystalline MnWO4 based on these sintering temperature conditions. As the amount of rare earth ions was changed, the magnetic and luminescent characteristics were enhanced; however, after 0.1 mol.%, the luminescent characteristics decreased due to the concentration quenching phenomenon. In addition, a composite was prepared by mixing MnWO4 powder, with enhanced magnetism and luminescence properties due to the addition of dysprosium, with epoxy. To one of the two prepared composites a magnetic field was applied to induce alignment of the MnWO4 particles. Aligned particles showed stronger luminescence than the composite sample prepared with unsorted particles. As a result of this, it was suggested that it can be used as phosphor and a photosensitizer by utilizing the magnetic and luminescent properties of the synthesized MnWO4 powder with the addition of rare earth ions.


1989 ◽  
Vol 162-164 ◽  
pp. 1277-1278 ◽  
Author(s):  
Kazuko Sekizawa ◽  
Yoshiki Takano ◽  
Takimichi Inaba

The theory that has been developed for rare-earth ions in crystals is here applied to the double nitrates. The paramagnetic resonance data and certain spectroscopic properties of the different rare-earth double nitrates, depending as they do on the crystalline electric field at a rare-earth ion, are related to the six parameters through which the field is defined. It is found that most of the experimental results can be fitted to values of the parameters that vary in a systematic fashion along the rare-earth series.


2016 ◽  
Vol 16 (4) ◽  
pp. 4029-4034 ◽  
Author(s):  
Chunxia Liu ◽  
Lixia Yang ◽  
Dan Yue ◽  
Mengnan Wang ◽  
Lin Jin ◽  
...  

Rare earth ions (Tb3+, Eu3+) doped CaWO4 microstructures were synthesized by a facile hydrothermal route without using any templates and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectrum. The results indicate that the asprepared samples are well crystallized with scheelite structure of CaWO4, and the average diameter of the microstructures is 2∼4 μm. The morphology of CaWO4:Eu3+ microstructures can be controllably changed from microspheres to microflowers through altering the doping concentration of Eu3+ from 3% to 35%, and the microflowers are constructed by a number of CaWO4:Eu3+ nanoflakes. Under the excitation of UV light, the emission spectrum of CaWO4:Eu3+ is composed of the characteristics emission of Eu3+ 5D0-7FJ (J = 1, 2, 3, 4) transitions, and that of CaWO4:Tb3+ is composed of Tb3+ 5D4-7FJ (J = 6, 5, 4, 3) transitions. Both of the optimal doping concentrations of Tb3+ and Eu3+ in CaWO4 microstructures are about 5%.


RSC Advances ◽  
2015 ◽  
Vol 5 (105) ◽  
pp. 86219-86236 ◽  
Author(s):  
Xiangfu Wang ◽  
Qing Liu ◽  
Yanyan Bu ◽  
Chun-Sheng Liu ◽  
Tao Liu ◽  
...  

Optical temperature sensing is a promising method to achieve the contactless temperature measurement and large-scale imaging. The current status of optical thermometry of rare-earth ions doped phosphors is reviewed in detail.


Sign in / Sign up

Export Citation Format

Share Document