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Articoli di riviste sul tema "RARE EARTH DOPED"

Autore: Grafiati

Pubblicato: 16 settembre 2023

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1

Petermann, K., G. Huber, L. Fornasiero, S. Kuch, E. Mix, V. Peters e S. A. Basun. "Rare-earth-doped sesquioxides". Journal of Luminescence 87-89 (maggio 2000): 973–75. http://dx.doi.org/10.1016/s0022-2313(99)00497-4.

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2

Xie, Rong Jun, Mamoru Mitomo e Naoto Hirosaki. "Luminescence Properties of Rare-Earth Doped α-SiAlONs". Key Engineering Materials 317-318 (agosto 2006): 797–802. http://dx.doi.org/10.4028/www.scientific.net/kem.317-318.797.

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Rare-earth doped Ca-α-SiAlON phosphors, with the compositions of (Ca1-3/2xREx)m/2Si12-m-nAlm+nOnN16-n (RE = Ce, Sm, Eu, Tb, Yb and Dy, 0.5 ≤ m = 2n ≤ 3.0), were prepared by reaction at 1700oC for 2h under 10 atm N2. The concentration of rare earths varied from 3 to 30 at% with respect to Ca. The photoluminescence properties of the powders were investigated at room temperature. The results show that (i) strong visible emissions are observed in rare-earth doped Ca-α-SiAlONs; (ii) the emission properties can be optimized by tailoring the activator concentration and the composition of the α-SiAlON host crystal; and (iii) the yellow Eu2+-doped Ca-α-SiAlON phosphors can be used in warm white LEDs.

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3

Dejneka, M. J., A. Streltsov, S. Pal, A. G. Frutos, C. L. Powell, K. Yost, P. K. Yuen, U. Muller e J. Lahiri. "Rare earth-doped glass microbarcodes". Proceedings of the National Academy of Sciences 100, n. 2 (6 gennaio 2003): 389–93. http://dx.doi.org/10.1073/pnas.0236044100.

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4

Zavada, John M., Tom Gregorkiewicz e Andrew J. Steckl. "Rare earth doped semiconductors III". Materials Science and Engineering: B 81, n. 1-3 (aprile 2001): 1–2. http://dx.doi.org/10.1016/s0921-5107(00)00666-8.

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5

Vetrone, Fiorenzo. "(Invited) Rare Earth Doped Nanoparticles". ECS Meeting Abstracts MA2022-02, n. 36 (9 ottobre 2022): 1319. http://dx.doi.org/10.1149/ma2022-02361319mtgabs.

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Luminescent nanomaterials that can be excited, as well as emit, in the near-infrared (NIR) have been investigated for use in a plethora of applications including nanomedicine, nanoelectronics, biosensing, bioimaging, photovoltaics, photocatalysis, etc. The use of NIR light for excitation mitigates some of the drawbacks associated with high-energy (UV or blue) excitation, for example, little to no background autofluorescence from the specimen under investigation as well as no incurred photodamage. Moreover, one of the biggest limitations is of course, that of penetration. As such, NIR light can penetrate tissues much better than high-energy light especially when these wavelengths lie within the three biological windows (BW-I: 700-950, BW-II: 1000-1350, BW-III: 1550-1870 nm) where tissues are optically transparent. At the forefront of NIR excited nanomaterials are rare earth doped nanoparticles, which due to their 4f electronic energy states can undergo conventional (Stokes) luminescence and emit in the three NIR biological windows. However, unlike other classes of nanoparticles, they can also undergo a multiphoton process (known as upconversion) where the NIR excitation light is converted to higher energies resulting in anti-Stokes luminescence spanning the UV-visible-NIR regions. Perhaps the biggest impact of such materials would be in the field of disease diagnostics and therapeutics, now commonly referred to as theranostics. Due to the versatility of their optical properties, it now becomes possible to generate high-energy light (UV or blue) in situ to trigger other light activated therapeutic modalities (i.e. drug release) while using the NIR emission for diagnostics (i.e. bioimaging, nanothermometry). Here, we present the synthesis of various NIR excited (and emitting) rare earth doped core/shell (and multishell) nanoparticles and demonstrate how their luminescence properties can be exploited for potential use in diverse biomedical applications.

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6

Sushama, D., e P. Predeep. "Thermal and Optical Studies of Rare Earth Doped Tungston–Tellurite Glasses". International Journal of Applied Physics and Mathematics 4, n. 2 (2014): 139–43. http://dx.doi.org/10.7763/ijapm.2014.v4.271.

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7

Bai, Tao, e Shi Gen Zhu. "Preparation and Properties of Rare Earth-Doped TiO₂ Thin Films by Sol-Gel Process". Advanced Materials Research 1033-1034 (ottobre 2014): 1235–38. http://dx.doi.org/10.4028/www.scientific.net/amr.1033-1034.1235.

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Rare earth doped titaniumdioxide (TiO2) thin films (rare earth-doped TiO2) have been successfully prepared on a glass substrate by a sol–gel route. After the rare earth-doped TiO2thin films were calcined at 773K for 1h, the effect of rare earth-doping on the properties were investigated using X-ray diffraction (XRD), scanning electronmicroscopy (SEM), ultraviolet–visible spectroscopy and thermogravimetric techniques (TG/DTG). The XRD results showed that rare earth-doped TiO2thin films contained only a single crystalline phase of anatase TiO2after calcining at 773K for 1h. SEM micrographs showed that rare earth-doped TiO2thin films have smooth surfaces containing granular nanocrystallines and are without cracks. The UV–vis absorption spectra showed that the absorption of the rare earth-doped TiO2thin films has a red-shift. From ambient to 1273K, it is about 12% of mass loss because of the volatilizing of water and organic and the phase transformation.

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8

Simoncic, Petra, e Alexandra Navrotsky. "Energetics of rare-earth-doped hafnia". Journal of Materials Research 22, n. 4 (aprile 2007): 876–85. http://dx.doi.org/10.1557/jmr.2007.0133.

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The enthalpies of formation of rare-earth (RE)-doped Hf1−xRExO2−x/2 solid solutions (RE = Sm, Gd, Dy, Yb; x = 0.25 to 0.62) with respect to the oxide end members, monoclinic HfO2 and C-type REO1.5, were determined using oxide melt solution calorimetry. The enthalpies of formation fit a function quadratic in composition. The strongly negative interaction parameters in all solid solutions confirm a strong tendency for short-range order. Though strongly negative for all systems, the interaction parameters become less negative with increasing ionic potential (decreasing RE radius). Crystallization energetics were investigated for amorphous coprecipitation products with x = 0.4. The energy difference between the crystalline (fluorite and pyrochlore) and amorphous phases decreases with decreasing dopant radius. This suggests that systems doped with small RE ions have more similar local structures in the fluorite and amorphous phases. These observations may result in a smaller kinetic barrier to recrystallization and account for the greater radiation resistance of materials with smaller RE cations.

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9

HU, Qiang, Xue BAI e Hong-wei SONG. "Rare Earth Ion Doped Perovskite Nanocrystals". Chinese Journal of Luminescence 43, n. 01 (2022): 8–25. http://dx.doi.org/10.37188/cjl.20210330.

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10

FUJIMURA, Masatoshi. "Rare-earth doped LiNbO3 waveguide lasers". Review of Laser Engineering 27, Supplement (1999): 138–39. http://dx.doi.org/10.2184/lsj.27.supplement_138.

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11

Radoczy, T., Kristof Kovacs e N. Sarzo. "Rare Earth Metal Doped Barium Titanates". Materials Science Forum 589 (giugno 2008): 143–48. http://dx.doi.org/10.4028/www.scientific.net/msf.589.143.

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High purity as well as Ce-, Pr- and Y-doped polycrystalline BaTiO3 ceramics were prepared by wet chemical synthesis. Dielectric constant as well as dielectric loss of dry pressed and sintered ceramics show dielectric constant above 20000 for samples containing 0.5 % Ce accompanied by semiconducting properties. X-ray diffraction studies confirmed Ti being substituted by Ce an Y, while Pr substitutes Ba ions.

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12

Duling, Irl N. "Dispersion in rare-earth-doped fibers". Optics Letters 16, n. 24 (15 dicembre 1991): 1947. http://dx.doi.org/10.1364/ol.16.001947.

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13

Mescia, Luciano, Francesco Prudenzano, Marco De Sario, Tommaso Palmisano, Maurizio Ferrari e Giancarlo C. Righini. "Design of Rare-Earth-Doped Microspheres". IEEE Photonics Technology Letters 22, n. 6 (marzo 2010): 422–24. http://dx.doi.org/10.1109/lpt.2009.2039932.

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14

Schweizer, T., D. W. Hewak, D. N. Payne, T. Jensen e G. Huber. "Rare-earth doped chalcogenide glass laser". Electronics Letters 32, n. 7 (1996): 666. http://dx.doi.org/10.1049/el:19960430.

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15

Geburt, S., D. Stichtenoth, S. Müller, W. Dewald, C. Ronning, J. Wang, Y. Jiao, Y. Y. Rao, S. K. Hark e Quan Li. "Rare Earth Doped Zinc Oxide Nanowires". Journal of Nanoscience and Nanotechnology 8, n. 1 (1 gennaio 2008): 244–51. http://dx.doi.org/10.1166/jnn.2008.n05.

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Zinc oxide (ZnO) nanowires were grown via thermal transport and subsequently doped with different concentrations of Tm, Yb, and Eu using ion implantation and post annealing. High ion fluences lead to morphology changes due to sputtering; however, freestanding nanowires become less damaged compared to those attached to substrates. No other phases like rare earth (RE) oxides were detected, no amorphization occurs in any sample, and homogeneous doping with the desired concentrations was achieved. Photoluminescence measurements demonstrate the optical activation of trivalent RE-elements and the emission of the characteristic intra-4f-luminescence of the respective RE atoms, which could be assigned according to the Dieke-diagram. An increasing RE concentration results into decreasing luminescence intensity caused by energy transfer mechanisms to non-radiative remaining implantation defect sites. Furthermore, low thermal quenching was observed due to the considerable wide band gap of ZnO.

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16

Almeida, Rui M., Paulo J. Morais e M. Clara Gonçalves. "Rare earth doped fluorozirconate glass films". Journal of Non-Crystalline Solids 213-214 (maggio 1997): 251–55. http://dx.doi.org/10.1016/s0022-3093(96)00668-0.

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17

Chen, Hua, Ying Chen, Yun Liu, Hongzhou Zhang, Chi Pui Li, Zongwen Liu, Simon P. Ringer e Jim S. Williams. "Rare-earth doped boron nitride nanotubes". Materials Science and Engineering: B 146, n. 1-3 (gennaio 2008): 189–92. http://dx.doi.org/10.1016/j.mseb.2007.07.064.

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18

Clara Gonçalves, M., Luís F. Santos e Rui M. Almeida. "Rare-earth-doped transparent glass ceramics". Comptes Rendus Chimie 5, n. 12 (dicembre 2002): 845–54. http://dx.doi.org/10.1016/s1631-0748(02)01457-1.

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19

Moncorgé, R., P. Ruterana e J. Zavada. "Rare earth-doped materials for photonics". Materials Science and Engineering: B 105, n. 1-3 (dicembre 2003): 1. http://dx.doi.org/10.1016/j.mseb.2003.08.003.

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20

Yanagida, Takayuki. "Study of rare-earth-doped scintillators". Optical Materials 35, n. 11 (settembre 2013): 1987–92. http://dx.doi.org/10.1016/j.optmat.2012.11.002.

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21

Bhushan, S., e Deepti Diwan. "Photoconductivity of rare earth doped ZnO". Journal of Materials Science Letters 5, n. 7 (luglio 1986): 723–24. http://dx.doi.org/10.1007/bf01730227.

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22

Lucas, Jacques, e Jean-Luc Adam. "Rare-earth doped fluoride glass fibres". Journal of Alloys and Compounds 180, n. 1-2 (marzo 1992): 27–35. http://dx.doi.org/10.1016/0925-8388(92)90360-l.

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23

Mihaylova, Emilia, e Stoyan Stoyanov. "Investigation of rare earth doped tgs". Ferroelectrics 174, n. 1 (dicembre 1995): 283–88. http://dx.doi.org/10.1080/00150199508215026.

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24

Honkanen, S., S. I. Najafi e W. J. Wang. "Composite rare-earth-doped glass waveguides". Electronics Letters 28, n. 8 (1992): 746. http://dx.doi.org/10.1049/el:19920472.

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25

Vetrone, Fiorenzo. "Rare Earth Doped Nanoparticles for Theranostics". ECS Meeting Abstracts MA2020-02, n. 66 (23 novembre 2020): 3327. http://dx.doi.org/10.1149/ma2020-02663327mtgabs.

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26

Hu, Qingsong, Zha Li, Zhifang Tan, Huaibing Song, Cong Ge, Guangda Niu, Jiantao Han e Jiang Tang. "Rare Earth Ion-Doped CsPbBr3 Nanocrystals". Advanced Optical Materials 6, n. 2 (18 dicembre 2017): 1700864. http://dx.doi.org/10.1002/adom.201700864.

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27

Milanova, Maria, e Martin Tsvetkov. "Rare Earths Doped Materials". Crystals 11, n. 3 (26 febbraio 2021): 231. http://dx.doi.org/10.3390/cryst11030231.

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Тhe properties of the Rare Earth Elements allow a wide range of applications in optoelectronics, fiber amplifiers, solid-state lasers, telecommunications, biosensing, and photocatalysis, just to mention a few [...]

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28

He, Qingyun, Xingqiang Liu, Feng Li, Fang Li, Leiming Tao e Changlin Yu. "Effect of Light and Heavy Rare Earth Doping on the Physical Structure of Bi2O2CO3 and Their Performance in Photocatalytic Degradation of Dimethyl Phthalate". Catalysts 12, n. 11 (22 ottobre 2022): 1295. http://dx.doi.org/10.3390/catal12111295.

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In order to solve the problem of environmental health hazards caused by phthalate esters, a series of pure Bi2O2CO3 and light (La, Ce, Pr, Nd, Sm and Eu) and heavy (Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) rare earth-doped Bi2O2CO3 samples were prepared by hydrothermal method. The crystalline phase composition and physical structure of the samples calcined at 300 °C were studied, and we found that the rare earth ion doping promoted the transformation of Bi2O2CO3 to β-Bi2O3 crystalline phase, thus obtaining a mixed crystal phase photocatalyst constituted by rare earth-ion-doped Bi2O2CO3/β-Bi2O3. The Bi2O3/Bi2O2CO3 heterostructure had a lower band gap and more efficient charge transfer. The fabricated samples were applied to the photocatalytic degradation of dimethyl phthalate (DMP) under a 300 W tungsten lamp, and it was found that the rare earth ion doping enhanced the photocatalytic degradation activity of DMP, in which the heavy rare earth of Er-doped sample reached 78% degradation for DMP at 150 min of light illumination. In addition, the doping of rare earths resulted in a larger specific surface area and a stronger absorption of visible light. At the same time, the formation of Bi2O2CO3/β-Bi2O3 heterogeneous junction enhanced the separation efficiency of photogenerated electrons and holes.

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Li, J., O. H. Y. Zalloum, T. Roschuk, C. L. Heng, J. Wojcik e P. Mascher. "Light Emission from Rare-Earth Doped Silicon Nanostructures". Advances in Optical Technologies 2008 (13 maggio 2008): 1–10. http://dx.doi.org/10.1155/2008/295601.

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Rare earth (Tb or Ce)-doped silicon oxides were deposited by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD). Silicon nanocrystals (Si-ncs) were formed in the silicon-rich films during certain annealing processes. Photoluminescence (PL) properties of the films were found to be highly dependent on the deposition parameters and annealing conditions. We propose that the presence of a novel sensitizer in the Tb-doped oxygen-rich films is responsible for the indirect excitation of the Tb emission, while in the Tb-doped silicon-rich films the Tb emission is excited by the Si-ncs through an exciton-mediated energy transfer. In the Ce-doped oxygen-rich films, an abrupt increase of the Ce emission intensity was observed after annealing at 1200∘C. This effect is tentatively attributed to the formation of Ce silicate. In the Ce-doped silicon-rich films, the Ce emission was absent at annealing temperatures lower than 1100∘C due to the strong absorption of Si-ncs. Optimal film compositions and annealing conditions for maximizing the PL intensities of the rare earths in the films have been determined. The light emissions from these films were very bright and can be easily observed even under room lighting conditions.

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Bai, Qiongyu, Zhijun Wang, Panlai Li, Shuchao Xu, Ting Li e Zhiping Yang. "Zn2−aGeO4:aRE and Zn2Ge1−aO4:aRE (RE = Ce3+, Eu3+, Tb3+, Dy3+): 4f–4f and 5d–4f transition luminescence of rare earth ions under different substitution". RSC Advances 6, n. 104 (2016): 102183–92. http://dx.doi.org/10.1039/c6ra21932b.

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Generally, luminescent properties of rare earth ions doped host can be tuned by controlling the host composition, that is, when substituted for different cations of host, the rare earths ions can present different characteristics.

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Yamada, Tetsuo, Takeshi Yamao e Shinichi Sakata. "Development of SiAlON - From Mechanical to Optical Applications". Key Engineering Materials 352 (agosto 2007): 173–78. http://dx.doi.org/10.4028/www.scientific.net/kem.352.173.

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Various rare-earth-doped α-SiAlON powders with high purity were prepared to study mechanical and optical properties of SiAlON-based functional materials in connection with ionic radius and electronic structure of rare-earth elements. Single phase rare-earth-doped α-SiAlON powders were obtained at a temperature as low as 1873 K by heating powder mixtures of rare-earth oxide, AlN and highly active ultrafine amorphous Si3N4. Bending strength of highly dense rare-earth-doped α/β-SiAlON-based ceramics was increased with decreasing radii of rare-earth ions, i.e., Yb-SiAlON-based ceramics exhibited excellent high-temperature strength and oxidation resistance caused by the small ionic radius of ytterbium. As for optical application, α-SiAlON is an excellent host lattice with good thermal and chemical stability for doping rare-earth element which activates photoluminescence. Europium-doped Ca-α-SiAlON phosphor formulated as CaxEuy(Si,Al)12(O,N)16 (where 0<x+y<2) was prepared to obtain high quality phosphor with high brightness and desired emission characteristics. Photoluminescence spectra of the resultant Europium-doped Ca-α-SiAlON exhibited high emission intensity at peak wavelength of 580-600 nm giving the better yellow color tone than Cerium-doped yttrium aluminum garnet for applying white LED. It was demonstrated that nitrides or oxynitrides were the innovative materials for the diverse range of high performance specialty applications.

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ZHAO, XINWEI, SUSUMU HARAKO, SHINRI NOGUCHI e SHUJI KOMURO. "SYSTHESIS AND OPTICAL PROPERTIES OF RARE EARTHS DOPED NANO-SEMICONDUCTORS AND THEIR APPLICATIONS". International Journal of Modern Physics B 16, n. 28n29 (20 novembre 2002): 4294–301. http://dx.doi.org/10.1142/s0217979202015297.

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Er and Yb have been doped into nanocrystalline Si and ZnO thin films. Sharp and intense photoluminescence (PL) lines related to intra-4f transitions in the rare earth ions were observed. The optical transition dynamics of the rare earth ions were investigated by time-resolved PL measurements. It was demonstrated that a nano-meter sizing of Si widened the energy bandgap and led to an increase of doping densities of the rare earths. It was also shown that the Er-related PL gave rise to different features under direct and indirect excitations indicating a strong interaction of electron-hole pairs in the host with 4f electrons in the rare earth ions. A co-doping effect of Yb and Er into nanocrystalline Si was presented also. Our results suggested a rare earth-rare earth coupling between the Yb 3+ ions and the Er 3+ ions, which transferred the energy from Yb to Er and enhanced the 1.54 μm PL of Er.

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Kellerman, D. G., M. O. Kalinkin, D. A. Akulov, R. M. Abashev, V. G. Zubkov, A. I. Surdo, N. I. Medvedeva e M. V. Kuznetsov. "On the energy transfer in LiMgPO4 doped with rare-earth elements". Journal of Materials Chemistry C 9, n. 34 (2021): 11272–83. http://dx.doi.org/10.1039/d1tc02211c.

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The TL and RL signals in LiMgPO4:Sm, Gd, Tb, Dy, Tm originate from f–f transitions in rare earth elements, while the rare earths in LiMgPO4:Er, Ho, Nd only greatly enhance the signals of the phosphate matrix as a result of energy transfer.

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Liu, Chun Feng, Feng Ye, Yu Zhou, Qing Chang Meng e Yong Liang Wang. "Microstructure of Different Rare-Earth-Doped α-Sialon Ceramics". Key Engineering Materials 336-338 (aprile 2007): 1182–84. http://dx.doi.org/10.4028/www.scientific.net/kem.336-338.1182.

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The densified α-sialon ceramics with the compositions RE0.333Si10Al2ON15 (RE= Yb,Y, Dy, Sm and Nd) were prepared by a two-step hot-pressing sintering. The ceramics doped with smaller cations (Yb3+, Y3+ and Dy3+) are fully composed of α-sialon, while the larger cation-doped ceramics (Sm3+ and Nd3+) exist a few M′ (RE2Si3-xAlxO3+xN4-x) phases. A small amount of β-sialon phases are also found in the Nd-doped sialon. Microstructure observation indicates that Yb-α-sialon consists of equiaxial grains, but when increasing the radius of the doped cations, the elongated α-sialon grains form and the aspect ratio of grain increases slightly. TEM observation indicated that almost no intergranular phases exist in the α-sialon doped with smaller cations, but a few exist in Sm- and Nd-doped α-sialon. Some elongated α-sialon grains with grain core were found. EDX results suggest that the compositions of the grain shell and that of the core are different. Surrounding the grain core, some misfit dislocations were seen.

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Moncorgé, R., L. D. Merkle e B. Zandi. "UV-Visible Lasers Based on Rare-Earth Ions". MRS Bulletin 24, n. 9 (settembre 1999): 21–26. http://dx.doi.org/10.1557/s088376940005301x.

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An issue on novel applications of materials doped with rare-earth (RE) ions can scarcely fail to address lasers, but it need not address all RE-based lasers. Some Nd3+ -doped lasers, particularly Nd:YAG (Y3Al5O12, yttrium aluminum garnet), emitting light with a wavelength of 1064 nm, are very well-established commercial products—by no means novelties.1 Some other near-infrared (NIR) lasers, based on Er3+ or Tm3+, are also available commercially. That wavelength region is relatively easy for RE laser ions, involving energy spacings between initial and final energy levels small enough to give large stimulated emission cross sections for useful, long upper-state life-times, yet large enough to minimize thermal deexcitation mechanisms. On the other hand, RE-doped lasers for ultraviolet (UV) and visible wavelengths are quite novel, since efficient laser operation is more difficult to achieve in these spectral ranges. Intriguing progress on such devices has been made in recent years, driven by several important applications.In this article, we begin by noting some of the alternative ways to obtain laser light at these wavelengths, including their advantages and drawbacks. We then discuss basic properties of RE-doped laser materials and how these can be advantageous. We then review a few of the most important and recent RE-doped laser materials and techniques for obtaining UV and visible output.

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Steckl, Andrew J., e John M. Zavada. "Photonic Applications of Rare-Earth-Doped Materials". MRS Bulletin 24, n. 9 (settembre 1999): 16–20. http://dx.doi.org/10.1557/s0883769400053008.

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The elements of the lanthanide series, from Ce (atomic number 58) to Yb (atomic number 70), form a group of chemically similar elements that have in common a partially filled 4f shell. These so-called “rare earth” (RE) elements usually take on a 3+ ionic state (RE3+). Because the 4f electronic-energy levels of each lanthanide ion are shielded from external fields by 5s2 and 5p6 outer-shell electrons, RE3+ energy levels are predominantly independent of their surroundings.The characteristic energy levels of 4f electrons of the trivalent RE elements have been investigated in detail by Gerhard Heinrich Dieke and co-workers and were reported approximately 30 years ago. The Dieke diagram showing RE3+ energy levels is a familiar tool of scientists and engineers working with RE elements. However, the history of RE elements goes back to the year 1787 in the small Swedish town of Ytterby near Stockholm and to the gifted amateur mineralogist and military man Lt. Carl Axel Arrhenius. Arrhenius discovered an unusual black mineral in Ytterby (perceived initially as much rarer in occurrence and in concentration than the common ores or earths of aluminum, calcium, etc.). Many new elements were discovered by various chemists upon analysis of this black stone and others like it. The names given to these elements are variations of the location where the first discovery was made: yttrium, ytterbium, terbium, and erbium. The history of RE elements is fascinating and involves many other famous names in science: Berzelius, Gadolin, Bunsen.The properties of these elements and their multifaceted applications to science and industry are equally fascinating and have remained important to this day. Commercial applications of RE elements began after World War II, when their available quantity and purity were greatly enhanced by improved separation techniques developed as a part of the Manhattan Project. Until fairly recently, the main industrial application of RE elements has been in permanent magnets. The unpaired 4f electrons result in some RE elements having the highest magnetic moments of any element. The development and applications of RE magnets are reviewed in a very interesting article by Livingston3 in a previous MRS Bulletin issue. In this issue of MRS Bulletin, we have taken as our aim to review some of the properties and applications of RE elements relevant to photonics.

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Dejneka, M., e B. Samson. "Rare-Earth-Doped Fibers for Telecommunications Applications". MRS Bulletin 24, n. 9 (settembre 1999): 39–45. http://dx.doi.org/10.1557/s0883769400053057.

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Primarily to meet the dramatic increase in Internet traffic, a substantial expansion in new fiber-optic networks has been seen in the last few years, increasing the total amount of transmission fiber deployed in the field. However, increased capacity has also been achieved by utilizing more of the available bandwidth present in the currently installed fiber. A key component in facilitating this increase in bandwidth is the erbium-doped fiber amplifier (EDFA), which provides efficient broad-band gain in the 1530–1560-nm telecommunications window. Erbium-doped glasses can be drawn into low-loss fiber, and the width of the gain band can be controlled with glass composition. With appropriate composition and design, EDFAs can simultaneously amplify 32 or more wavelengths, providing a 32-fold increase in data capacity over single-channel systems. These devices can boost signal strength by a factor of 1000, with high reliability and low noise at data rates exceeding 1 Tbit/s. In this article, we review some of the properties that are key to the success of EDFAs and discuss the potential for other rare-earth-doped glass-fiber combinations that may find possible applications in future telecommunications networks.Fiber optics have revolutionized the telecommunications industry, providing more information capacity and greater distances between signal boosters than copper wire and coaxial cable. The attenuation in coaxial systems increases exponentially with signal frequency, making high-speed transmission over long distances impractical. The best copper systems have a bandwidth of about 10 Mbit/s and are limited to lengths of less than 200 m at high data rates. In contrast, the attenuation of SiO2 optical fibers is low and independent of signal frequency, thus optical fiber can easily support 100 Gbit/s (10,000 times the capacity of copper) over 80 km and is currently only limited by the speed of the transmission and receiving electronics, with capacities in excess of 50 Tbit/s theoretically possible.1 For links in excess of 80 km, signal amplification is necessary to prevent total loss of the signal. In the 1980s, amplification was done with electronic devices called repeaters that detected the light, converted it to an electronic signal, amplified, retimed, and then retransmitted it as an optical pulse.The field of optical telecommunications has itself undergone a revolution. In the late 1980s, the invention of the all-optical amplifier allowed for simultaneous amplification of multiple channels in a single optical fiber each at a different wavelength or color of light. SiO2 fibers have a minimum in attenuation in the infrared (IR) portion of the optical spectrum near 1550 nm, as shown in Figure 1. The EDFA fortuitously provides high gain and low noise in the 1530-1560-nm spectral window. This technology now enables simultaneous amplification of 32 channels in a single fiber without the need for optical-to-electronic conversion. Thus single-fiber capacities of 320 Gbit/s are currently being deployed today. To perform this electronically, each channel would have to be separated (demultiplexed), amplified by its own costly repeater, and then recombined (multiplexed) in the fiber. Researchers are now perfecting 100-channel EDFAs in the lab.

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38

Ballato, John, John S. Lewis e Paul Holloway. "Display Applications of Rare-Earth-Doped Materials". MRS Bulletin 24, n. 9 (settembre 1999): 51–56. http://dx.doi.org/10.1557/s0883769400053070.

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The human eye places remarkably stringent requirements on the devices we use to illuminate objects or generate images. Exceedingly small deviations in color or contrast from what we consider natural are easily judged by the brain to be fake. Such cognition drives consumer practice, so great efforts have been made for over a century to synthesize emissive materials that match the response functions associated with the human perception of color. This is an extremely difficult task, given the diverse range of considerations, some of which include whether (1) the display is viewed under artificial light or natural sunlight, (2) the images are stationary or moving, and (3) the rendering of depth in a two-dimensional image is believable.Established technologies including cathode-ray tubes (CRTs), vacuum fluorescent displays (VFDs), lamps, and x-ray phosphors have made possible a wide variety of display and imaging devices. However, continued advances are required to increase brightness, contrast, color purity, resolution, lifetime, and viewing angle while still lessening the cost, weight, volume, and power consumption. Mature or emerging technologies that address these issues include thin-film electroluminescent (TFEL) displays, liquid-crystal displays (LCDs),8 field-emission displays (FEDs),9 and plasma displays (PDs).10-12 Each of these technologies uses luminescent materials consisting typically of an activator from which light is emitted and a host for low concentrations of the activator (typically >1% activator). The requirements of the host and activator are discussed in a later section. The luminescent material can exhibit either a narrow emission spectrum, useful for color displays, or a broadband emission, which can extend into multiple colors. In addition, with multiple activator/host combinations, a luminescent material can emit several colors and even white light. While LCDs are light valves, which may be used in a reflective mode and therefore do not require a luminescent material, low-light situations require a backlight generated by a luminescent material. Many of the most versatile, efficient activators are rare-earth (RE) elements, for reasons that will be discussed. The ability of RE ions to emit red, green, and blue light make them well suited for application in visible-display technologies. This article reviews dopant and host material systems, excitation mechanisms, and the factors that limit the achievable luminescent intensity and efficiency. Device configurations for modern displays are discussed, as are materials and structures for next-generation technologies. Since each display technology has different performance and operational requirements, only the basic characteristics will be discussed here to enable an appreciation of emission from RE activators. References to the literature are supplied to further direct the reader to more in-depth discussions.

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Hao, Shuwei, Guanying Chen e Chunhui Yang. "Sensing Using Rare-Earth-Doped Upconversion Nanoparticles". Theranostics 3, n. 5 (2013): 331–45. http://dx.doi.org/10.7150/thno.5305.

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ZHANG LONG, ZHANG JUN-JIE, QI CHANG-HONG, LIN FENG-YING e HU HE-FANG. "RARE EARTH DOPED AlF3-BASED FLOURIDE GLASS". Acta Physica Sinica 49, n. 8 (2000): 1620. http://dx.doi.org/10.7498/aps.49.1620.

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41

TANIGUCHI, Tomohiro, Koji FUJITA, Tsuguo ISHIHARA, Katsuhisa TANAKA e Kazuyuki HIRAO. "Triboluminescence of Rare-Earth-Doped Celsian Polycrystals." Journal of the Society of Materials Science, Japan 49, n. 6 (2000): 622–24. http://dx.doi.org/10.2472/jsms.49.622.

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42

Mattsson, Kent E. "Photo darkening of rare earth doped silica". Optics Express 19, n. 21 (26 settembre 2011): 19797. http://dx.doi.org/10.1364/oe.19.019797.

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43

Digonnet, M. J. "Guest editorial [Rare-earth-doped fiber devices]". IEEE Journal of Quantum Electronics 37, n. 9 (settembre 2001): 1109. http://dx.doi.org/10.1109/jqe.2001.945314.

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44

Li, Yuhang, Guillaume Vienne, Xiaoshun Jiang, Xinyun Pan, Xu Liu, Peifu Gu e Limin Tong. "Modeling rare-earth doped microfiber ring lasers". Optics Express 14, n. 16 (2006): 7073. http://dx.doi.org/10.1364/oe.14.007073.

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45

Jacobsohn, L. G., C. L. McPherson, K. B. Sprinkle, E. G. Yukihara, T. A. DeVol e J. Ballato. "Scintillation of rare earth doped fluoride nanoparticles". Applied Physics Letters 99, n. 11 (12 settembre 2011): 113111. http://dx.doi.org/10.1063/1.3638484.

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46

Veverka, Pavel, Ondřej Kaman, Karel Knížek, Pavel Novák, Miroslav Maryško e Zdeněk Jirák. "Magnetic properties of rare-earth-doped La0.7Sr0.3MnO3". Journal of Physics: Condensed Matter 29, n. 3 (16 novembre 2016): 035803. http://dx.doi.org/10.1088/1361-648x/29/3/035803.

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47

G r me, V., D. Lapraz, P. Iacconi, M. Benabdesselam, H. Pr vost e A. Baumer. "Thermoluminescence Mechanisms in Rare Earth Doped CaSO4". Radiation Protection Dosimetry 84, n. 1 (1 agosto 1999): 109–13. http://dx.doi.org/10.1093/oxfordjournals.rpd.a032696.

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48

Bush, T. S., A. V. Chadwick, C. R. A. Catlow, G. N. Greaves e R. A. Jackson. "Structure in rare earth doped β″-alumina". Radiation Effects and Defects in Solids 119-121, n. 2 (novembre 1991): 487–92. http://dx.doi.org/10.1080/10420159108220769.

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49

De Souza, Saulo Soares, e Ana Regina Blak. "Mixed dimers in rare-earth-doped fluorides". Radiation Effects and Defects in Solids 134, n. 1-4 (dicembre 1995): 117–21. http://dx.doi.org/10.1080/10420159508227195.

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50

Hamano, Fumio, Kunihiko Tanaka e Hisao Uchiki. "Upconversion Luminescence of Rare-Earth-Doped CaGa2S4". Japanese Journal of Applied Physics 44, n. 1B (24 gennaio 2005): 769–71. http://dx.doi.org/10.1143/jjap.44.769.

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