Rare-Earth Doped Silicon-Rich Silica: Evidence for Energy Transfer between Silicon Microclusters and Rare-Earth Ions

1994 ◽  
Vol 358 ◽  
Author(s):  
A.J. Kenyon ◽  
P.F. Trwoga ◽  
M. Federighi ◽  
C.W. Pitt
Keyword(s):  
Rare Earth ◽  
Visible Region ◽  
Rare Earth Ions ◽  
Excitation Wavelength ◽  
Rare Earth Ion ◽  
Absorption Bands ◽  
Strong Luminescence ◽  
Doped Silicon ◽  
Rare Earth Doped ◽  
The Rare Earth

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

Luminescent Properties of Rare Earth Doped AlF3-Based Glasses

1991 ◽  
Vol 244 ◽  
Author(s):  
L. R. Copeland ◽  
W. A. Reed ◽  
M. R. Shahriari ◽  
T. Iqbal ◽  
P. Hajcak ◽  
...  
Keyword(s):  
Rare Earth ◽  
Optical Fibers ◽  
Luminescent Properties ◽  
Rare Earth Ions ◽  
Ion Concentration ◽  
Fluoride Glass ◽  
Oxide Glasses ◽  
Low Loss ◽  
Rare Earth Ion ◽  
Rare Earth Doped

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.

Modified TiO2Structures with Enhanced Photoluminescence and Photocatalytic Activity

2021 ◽  
Vol 13 (2) ◽  
pp. 331-341
Author(s):  
Jinqi Wang ◽  
Guopeng Li ◽  
Wei Wang ◽  
Fuxia Li ◽  
Chuankai Yang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Rare Earth ◽  
Photocatalytic Degradation ◽  
Environmental Remediation ◽  
Rare Earth Ions ◽  
Shell Structures ◽  
Rare Earth Complex ◽  
Core Shell ◽  
Rare Earth Ion ◽  
The Rare Earth

Photocatalytic degradation of pollutants has attracted much attention because it can effectively solve the problem of environmental pollution. SiO2@Eu(TTA)3phen@TiO2 core-shell structures were successfully synthesized for the first time by a solvothermal method involving ultrasound assistance which can optimize the rare earth complex dispersibility and achieve strong emission intensity. SiO2@Eu3+@TiO2 core-shell structures were also successfully synthesized by a similar method. Photocatalytic activity analysis showed that the photocatalytic activity factor not only depended on the rare earth ion content, but also related to the structure and size of the TiO2 nanoparticles. Photocatalytic activity increased first and then decreased with the quantity of rare earth ions. Photocatalytic activity was also superior for hollow structures compared to solid structure. Photocatalytic activity of SiO2@TiO2 particles increased with the particle size, until the size increased to 450 nm. Rare earth ions content as well as particle structures and sizes affected efficiency for the photocatalytic degradation of methyl orange. Outstanding photocatalytic activity provides the composite particles with improved potential to purify aquatic contaminants and to meet the demands of future environmental remediation applications.

scholarly journals Simple Preparation of LaPO4:Ce, Tb Phosphors by an Ionic-Liquid-Driven Supported Liquid Membrane System

2019 ◽  
Vol 20 (14) ◽  
pp. 3424
Author(s):  
Jianguo Li ◽  
Hongying Dong ◽  
Fan Yang ◽  
Liangcheng Sun ◽  
Zhigang Zhao ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Rare Earth ◽  
High Efficiency ◽  
Liquid Membrane ◽  
Membrane System ◽  
Rare Earth Ions ◽  
Raw Material ◽  
Supported Liquid Membrane ◽  
Rare Earth Ion ◽  
The Rare Earth

In this work, LaPO4:Ce, Tb phosphors were prepared by firing a LaPO4:Ce, Tb precipitate using an ionic-liquid-driven supported liquid membrane system. The entire system consisted of three parts: a mixed rare earth ion supply phase, a phosphate supply phase, and an ionic-liquid-driven supporting liquid membrane phase. This method showed the advantages of a high flux, high efficiency, and more controllable reaction process. The release rate of PO43− from the liquid film under different types of ionic liquid, the ratio of the rare earth ions in the precursor mixture, and the structure, morphology, and photoluminescence properties of LaPO4:Ce, Tb were investigated by inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, Raman spectra, scanning electron microscopy, and photoluminescence emission spectra methods. The results showed that a pure phase of lanthanum orthophosphate with a monoclinic structure can be formed. Due to differences in the anions in the rare earth supply phase, the prepared phosphors showed micro-spherical (when using rare earth sulfate as the raw material) and nanoscale stone-shape (when using rare earth nitrate as the raw material) morphologies. Moreover, the phosphors prepared by this method had good luminescent properties, reaching a maximum emission intensity under 277 nm excitation with a predominant green emission at 543 nm which corresponded to the 5D4-7F5 transition of Tb3+.

Local symmetry and Z-scan analysis of ZnSe/Eu3+ doped sol–gel silica hosts

2010 ◽  
Vol 88 (7) ◽  
pp. 493-500 ◽  
Author(s):  
Siby Mathew ◽  
K. V. Arun Kumar ◽  
C. Sudarsanakumar ◽  
V. P.N. Nampoori ◽  
N. V. Unnikrishnan
Keyword(s):  
Rare Earth ◽  
Sol Gel ◽  
Glass Network ◽  
Local Symmetry ◽  
Wide Distribution ◽  
Rare Earth Ions ◽  
Saturable Absorption ◽  
Rare Earth Ion ◽  
Enhanced Absorption ◽  
The Rare Earth

Vibrational state side-band spectral analysis of silica matrices, doped with ZnSe/Eu3+ ions, associated with the excitation transition 7F0→5D2 is used to analyze the local asymmetry of the rare earth ions in the glass host. The large inhomogeneous linewidth for the ZnSe co-doped samples indicates the wide distribution of the Eu3+ ions in the matrix and is related to the flexibility of the local glass network. The fluorescence spectra reveal that the intensity of the characteristic emission of europium increases considerably in the presence of ZnSe particles. This phenomenon can be explained by the energy transfer resulting from electron–hole recombination in the ZnSe to the rare earth ion. Nonlinear optical absorption of the sample is also investigated at a wavelength of 532 nm, using open aperture Z-scan technique. The sample exhibits reversible saturable absorption (RSA), which is found to depend on excitation fluence. RSA is due to the enhanced absorption resulting from the electron dynamics in nano-crystallites.

Structural Studies of Rare-Earth Doped Phosphate Glasses

1996 ◽  
Vol 455 ◽  
Author(s):  
A. Matic ◽  
L. Börjesson ◽  
A. Wannberg ◽  
R. L. McGreevy
Keyword(s):  
Rare Earth ◽  
Phosphate Glasses ◽  
Rare Earth Ions ◽  
Structural Studies ◽  
Rare Earth Ion ◽  
A Value ◽  
A Chain ◽  
D Model ◽  
Rare Earth La ◽  
Rare Earth Doped

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.

Er3+-Doped Silicon Prepared by Laser Doping

1993 ◽  
Vol 301 ◽  
Author(s):  
T. Asatsuma ◽  
P. Dodd ◽  
J. F. Donegan ◽  
J. G. Lunney ◽  
J. Hegarty
Keyword(s):  
Rare Earth ◽  
Pulsed Laser ◽  
Earth Metal ◽  
Optically Active ◽  
Rare Earth Ions ◽  
Molten Layer ◽  
Laser Doping ◽  
Doped Silicon ◽  
Preliminary Study ◽  
The Rare Earth

ABSTRACTWe have carried out an investigation of the laser doping of Si with rare-earth ions. In this technique a silicon surface coated with a thin layer of the rare-earth metal is melted with a pulsed laser, the dopant is mixed in the molten layer, and incorporated in the crystal during regrowth. Er was chosen for the main part of our work as it is the best characterized of the rare-earth ions in Si. Luminescence is observed around 1.54µm and is assigned to optical transitions on Er3+ ions. This preliminary study shows that this new technique is viable for the production of optically active Er3+ in Si.

Analysis of thermal glow curves in rare-earth-doped CaF2 crystals

1969 ◽  
Vol 47 (15) ◽  
pp. 1637-1638 ◽  
Author(s):  
M. Schlesinger ◽  
A. Krishna Menon
Keyword(s):  
Rare Earth ◽  
Thermal Activation ◽  
Activation Energies ◽  
Rare Earth Ions ◽  
Hole Trapping ◽  
Order Of Kinetics ◽  
Close Proximity ◽  
Rare Earth Doped ◽  
Trapping Sites ◽  
The Rare Earth

The main parameters, that is, thermal activation energies, frequency factors, and order of kinetics, are calculated for some glow peaks in rare-earth-doped CaF2. From the results, it is inferred that the hole trapping sites are in close proximity to the rare-earth ions.

Rare Earth Doped Crystals for Quantum Information: Quantum Computing and Quantum Storage

2006 ◽  
Vol 518 ◽  
pp. 173-180
Author(s):  
Philippe Goldner ◽  
Olivier Guillot-Noël
Keyword(s):  
Quantum Computing ◽  
Rare Earth ◽  
Quantum Information ◽  
Solid State ◽  
Rare Earth Ions ◽  
Rare Earth Ion ◽  
Hyperfine Transitions ◽  
Information Research ◽  
Superposition States ◽  
Rare Earth Doped

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).

Infrared and Electronic Spectra of Rare Earth Perovskites: Ortho-Chromites, -Manganites and -Ferrites

1970 ◽  
Vol 24 (4) ◽  
pp. 436-445 ◽  
Author(s):  
G. V. Subba Rao ◽  
C. N. R. Rao ◽  
J. R. Ferraro
Keyword(s):  
Magnetic Properties ◽  
Rare Earth ◽  
Transition Metal ◽  
Ir Spectra ◽  
Electronic Spectra ◽  
Transition Metal Ions ◽  
Rare Earth Ions ◽  
Electronic Transitions ◽  
Rare Earth Ion ◽  
The Rare Earth

The electronic and ir spectra of rare earth perovskites of the general formula LnZO3, where Ln is the rare earth ion or yttrium and Z is Cr, Mn, or Fe, have been studied in detail. The results have been discussed in terms of crystallography, magnetic properties, covalency of Ln—O and Z—O bonds, and Goodenough's one electron energy diagrams. In all these compounds the rare earth ions do not markedly affect the electronic transitions of the transition metal ions; the 3 d electrons clearly exhibit localized behavior. Both the electronic and ir spectra of the LnZO3 perovskites are comparable to the spectra of the corresponding transition metal sesquioxides, Z2O3.

scholarly journals Collective Optical, FTIR, and Photoluminescence Spectra of CeO2 and/or Sm2O3-Doped Na2O–ZnO–P2O5 Glasses

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
M. A. Marzouk ◽  
H. A. ElBatal ◽  
Y. M. Hamdy ◽  
F. M. Ezz-Eldin
Keyword(s):  
Rare Earth ◽  
Rare Earth Ions ◽  
Spectral Studies ◽  
Luminescence Spectra ◽  
Ir Absorption ◽  
Photoluminescence Spectra ◽  
Absorption Bands ◽  
Infrared Spectral ◽  
Doped Glasses ◽  
The Rare Earth

Glasses with the Na2O–ZnO–P2O5 composition and doped with single CeO2, Sm2O3, or mixed dopants were melted and studied. Collective optical, photoluminescence, and FT-infrared spectral studies were carried out. CeO2-doped glasses show two extra UV absorption bands due to Ce4+ and Ce3+ ions while Sm2O3-doped samples reveal pronounced peaks collected into two segments from 367 to 472 nm and from 950 to 1623 nm which are characteristic of absorption from Sm3+ ions. The mixed dopants glasses show combined UV-visible–near-IR absorption peaks due to cerium (Ce4+, Ce3+) ions and samarium (Sm3+) ions. The photoluminescence spectra (PL) of the single CeO2-doped and Sm2O3-doped glasses and even the mixed dopant sample reveal luminescence spectra after excitation which are characteristic of the rare-earth ions. The intensities for both excited or emitted peaks are found to increase with the increase of the rare-earth percent. FTIR spectra of the glasses show pronounced vibrational peaks related to phosphate groups (Q2 and Q3 units) in accordance with the P2O5 percent (70 mol %).

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