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Статті в журналах з теми "Laser, Rare-earths, Spectroscopy"
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Tremblay, M. E., J. B. Simeonsson, B. W. Smith, and J. D. Winefordner. "Laser-Induced Double Resonance Ionic Fluorescence of Rare Earths in the Inductively Coupled Plasma." Applied Spectroscopy 42, no. 2 (February 1988): 281–85. http://dx.doi.org/10.1366/0003702884428185.
Повний текст джерелаАнотація:
Laser excitation of ionic fluorescence overcomes the problem of spectral interferences encountered when trace analysis of the rare earths is performed by atomic/ionic emission spectrometry in the inductively coupled plasma. Two pulsed, excimer pumped, tunable dye lasers are used to excite ionic fluorescence of rare earths in an inductively coupled plasma. Since several fluorescence lines have been observed after laser excitation, it is possible to draw partial energy level diagrams for lanthanum, ytterbium, europium, and lutetium. Detection limits, linear dynamic ranges, and sensitivities are also reported. This is the first time that two-step excited fluorescence has been observed for any rare earths in an inductively coupled plasma.
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Haider, AFMY, and Zulfiqar Hasan Khan. "Identification of Multiple Rare Earths and Other Associated Elements in Zircon by Laser-Induced Breakdown Spectroscopy." Journal of Bangladesh Academy of Sciences 44, no. 1 (August 10, 2020): 59–68. http://dx.doi.org/10.3329/jbas.v44i1.48564.
Повний текст джерелаАнотація:
Laser-induced breakdown spectroscopy (LIBS), which is a powerful technique for the detection of minor and trace elements in a sample, has been used to analyze the enriched zircon mineral collected from the beach sands of southern Bangladesh. In addition to zirconium, a large number of rare earth elements viz. cerium, lanthanum, praseodymium, neodymium, ytterbium, gadolinium, dysprosium, erbium, samarium, europium, holmium and yttrium and other associated elements like hafnium, niobium, tantalum, magnesium, calcium, sodium, titanium and iron along with non-metals like phosphorus and silicon were detected in the enriched zircon samples by the LIBS technique. To the best of our knowledge, this is the first time that multiple rare earth elements have been identified in natural zircon by LIBS.
Journal of Bangladesh Academy of Sciences, Vol. 44, No. 1, 59-68, 2020
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Manard, Benjamin T., E. Miller Wylie, and Stephen P. Willson. "Analysis of Rare Earth Elements in Uranium Using Handheld Laser-Induced Breakdown Spectroscopy (HH LIBS)." Applied Spectroscopy 72, no. 11 (May 22, 2018): 1653–60. http://dx.doi.org/10.1177/0003702818775431.
Повний текст джерелаАнотація:
A portable handheld laser-induced breakdown spectroscopy (HH LIBS) instrument was evaluated as a rapid method to qualitatively analyze rare earth elements in a uranium oxide matrix. This research is motivated by the need for development of a method to perform rapid, at-line chemical analysis in a nuclear facility, particularly to provide a rapid first pass analysis to determine if additional actions or measurements are warranted. This will result in the minimization of handling and transport of radiological and nuclear material and subsequent exposure to their associated hazards. In this work, rare earth elements (Eu, Nd, and Yb) were quantitatively spiked into a uranium oxide powder and analyzed by the HH LIBS instrumentation. This method demonstrates the ability to rapidly identify elemental constituents in sub-percent levels in a uranium matrix. Preliminary limits of detection (LODs) were determined with values on the order of hundredths of a percent. Validity of this methodology was explored by employing a National Institute of Standards and Technology (NIST) standard reference materials (SRM) 610 and 612 (Trace Elements in Glass). It was determined that the HH LIBS method was able to clearly discern the rare earths elements of interest in the glass or uranium matrices.
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Abedin, K. M., A. F. M. Y. Haider, M. A. Rony, and Z. H. Khan. "Identification of multiple rare earths and associated elements in raw monazite sands by laser-induced breakdown spectroscopy." Optics & Laser Technology 43, no. 1 (February 2011): 45–49. http://dx.doi.org/10.1016/j.optlastec.2010.05.003.
Повний текст джерела
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Martin, Madhavi, Daniel Hamm, Samir Martin, Steve Allman, Gary Bell, and Rodger Martin. "Micro-Laser-Induced Breakdown Spectroscopy: A Novel Approach Used in the Detection of Six Rare Earths and One Transition Metal." Minerals 9, no. 2 (February 12, 2019): 103. http://dx.doi.org/10.3390/min9020103.
Повний текст джерелаАнотація:
Laser-induced breakdown spectroscopy (LIBS) was undertaken using an instrument which used a high-powered microscope to deliver the light and tightly focused the low energy laser beam onto the surface of a solid sample. A micro-plasma was generated on the surface of the sample under test even though the amount of energy/pulse from a beam of 532 nm was <1 mJ. Rare earth elements such as europium, gadolinium, lanthanum, neodymium, praseodymium, samarium, and a transition metal, yttrium, were tested. These elements are important in nuclear fission reactions especially for estimation of actinide masses for non-proliferation “safeguards”. Each element was mixed in the graphite matrix in different percentages from 1% to 50% by weight and the LIBS spectra were obtained for each composition as well as after mixing each element in the same amount using oxides of the elements. The data for the 5% mixture of the rare earth elements with graphite powder along with the transition metal has been presented in this article. A micro-LIBS approach was used to demonstrate that these rare earth elements can be identified individually and in a complex mixture in glove boxes in which the microscope LIBS instrument is housed in a nuclear research environment.
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Ricci, Giulia, Andrea Maurizio Monti, Renato Pagano, Marco Martini, Luisa Caneve, and Gilberto Artioli. "Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz." Minerals 11, no. 12 (November 30, 2021): 1345. http://dx.doi.org/10.3390/min11121345.
Повний текст джерелаАнотація:
Quartz from La Sassa (Tuscany, Italy) presents a unique luminescence related to intrinsic and extrinsic defects in the crystal lattice due to the growth mechanisms in hydrothermal conditions. The bright fluorescence under the UV lamp was apparent to collectors since the early 1970s, and it entered the literature as a reference case of yellow-luminescent quartz. Early reports present the history of the discovery, the geological context, and preliminary luminescence measurements of the quartz nodules, suggesting various activators as potentially responsible of the peculiar luminescence effects: uranyl groups (UO22+), rare earths (Tb3+, Eu3+, Dy3+, Sm3+, Ce3+) and polycyclic aromatic compounds (PAH). Here, we report a full investigation of the La Sassa material, by a multi-analytical approach encompassing cathodoluminescence optical microscopy (OM-CL), laser-induced fluorescence (LIF), wavelength resolved thermally stimulated luminescence (WR-TSL), trace elements analysis by mass spectrometry (ICP-MS) and Raman spectroscopy (RS). The results provide a significant step forward in the interpretation of the luminescence mechanisms: the main luminescent centres are identified as alkali-compensated (mainly Li+ and Na+, K+ and H+) aluminum [AlO4/M+]0 centres substituting for Si, where the recombination of a self-trapped exciton (STE) or an electron at a nonbridging oxygen hole centre (NBOHC) are active.
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Pisarska, Joanna, and Wojciech Pisarski. "Replacement of glass-former B2O3 by GeO2 in amorphous host evidenced by optical methods." Photonics Letters of Poland 9, no. 4 (December 31, 2017): 113. http://dx.doi.org/10.4302/plp.v9i4.790.
Повний текст джерелаАнотація:
Two completely different glass-host matrices containing lead, i.e. borate and germanate glasses doped with erbium were studied. Replacement of glass-former B2O3 by GeO2 in amorphous host was evidenced by optical methods. The luminescence decay from the 4I13/2 upper laser state of Er3+ ions is relatively short, whereas up-converted emission signal is reduced definitely in borate glass containing lead due to its high B-O stretching vibrations. The results indicate that germanate glasses containing lead are promising for near-infrared luminescence and up-conversion applications. Full Text: PDF ReferencesR. Balda, A. Oleaga, J. Fernandez, J.M. Fdez-Navarro, "Spectroscopy and frequency upconversion of Er3+ ions in lead niobium germanate glasses", Opt. Mater. 24, 83 (2003). CrossRef H. Yamauchi, Y. Ohishi, "Spectroscopic properties of Er3+-doped PbO?Ga2O3?GeO2 glass for optical amplifiers", Opt. Mater. 27, 679 (2005). CrossRef W.A. Pisarski, Ł. Grobelny, J. Pisarska, R. Lisiecki, W. Ryba-Romanowski, "Spectroscopic properties of Yb3+ and Er3+ ions in heavy metal glasses", J. Alloys Compd. 509, 8088 (2011). CrossRef M.B. Saisudha, J. Ramakrishna, "Effect of host glass on the optical absorption properties of Nd3+, Sm3+, and Dy3+ in lead borate glasses", Phys. Rev. B 53, 6186 (1996). CrossRef C.K. Jayasankar, V. Venkatramu, S. Surendra Babu, P. Babu, "Luminescence properties of Dy3+ ions in a variety of borate and fluoroborate glasses containing lithium, zinc, and lead", J. Alloys Compd. 374, 22 (2004). CrossRef W.A. Pisarski et al. "Luminescence spectroscopy of rare earth-doped oxychloride lead borate glasses", J. Lumin. 131, 649 (2011). CrossRef M. Kochanowicz, W. Mazerski, J. Żmojda, K. Czajkowski, D. Dorosz, "Green upconversion emission in tellurite optical fibre codoped with Yb3+/Er3+", Phot. Lett. Poland 5, 35 (2013). CrossRef J. Dorosz, "Novel constructions of optical fibers doped with rare ? earth ions", Ceramics 86 (2005). CrossRef J. Żmojda, D. Dorosz, M. Kochanowicz, J. Dorosz, "Spectroscopic properties of Yb3+/Er3+ - doped antimony-phosphate glasses for fiber amplifiers", Phot. Lett. Poland 2, 76 (2010). CrossRef J. Dorosz, R. S. Romaniuk, "Development of Optical Fiber Technology in Poland", INTL J. Electron. Telecom. 57, 191 (2011). CrossRef Q.Y. Zhang et al. "Effects of PbF2 doping on structure and spectroscopic properties of Ga2O3?GeO2?Bi2O3?PbO glasses doped with rare earths", J. Appl. Phys. 99, 033510 (2006) CrossRef W.A. Pisarski, G. Dominiak-Dzik, W. Ryba-Romanowski, J. Pisarska, "Role of PbO substitution by PbF2 on structural behavior and luminescence of rare earth-doped lead borate glass", J. Alloys Compd. 451, 220 (2008). CrossRef M. Sołtys, J. Pisarska, L. Żur, T. Goryczka, W.A. Pisarski, "Influence of M2O3 (M = Al, Ga) glass modifiers on structure, thermal and spectroscopic properties of rare earth ions in lead phosphate based systems", Proc. SPIE 9228, 92280A (2014). CrossRef J. Janek, J. Pisarska, W.A. Pisarski, "Rare earth doped lead-free germanate glasses for modern photonics", Phot. Lett. Poland 6, 71 (2014). CrossRef W.A. Pisarski et al. "Infrared-to-visible conversion luminescence of Er3+ ions in lead borate transparent glass-ceramics", Opt. Mater. 31, 1781 (2009). CrossRef J. Pisarska, L. Żur, W.A. Pisarski, "Optical spectroscopy of Dy3+ ions in heavy metal lead-based glasses and glass?ceramics", J. Mol. Struct. 993, 160 (2011). CrossRef L. Żur, M. Sołtys, J. Pisarska, W.A. Pisarski, "Absorption and luminescence properties of terbium ions in heavy metal glasses", J. Alloys Compd. 578, 512 (2013). CrossRef W.A. Pisarski, L. Żur, M. Kowal, J. Pisarska, "Enhancement and quenching photoluminescence effects for rare earth ? Doped lead bismuth gallate glasses", J. Alloys Compd. 651, 565 (2015). CrossRef M. Shojiya, Y. Kawamoto, K. Kadono, "Judd?Ofelt parameters and multiphonon relaxation of Ho3+ ions in ZnCl2-based glass", J. Appl. Phys. 89, 4944 (2001). CrossRef
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Pawlik, Natalia, Barbara Szpikowska-Sroka, Tomasz Goryczka, Ewa Pietrasik, and Wojciech A. Pisarski. "Luminescence of SiO2-BaF2:Tb3+, Eu3+ Nano-Glass-Ceramics Made from Sol–Gel Method at Low Temperature." Nanomaterials 12, no. 2 (January 14, 2022): 259. http://dx.doi.org/10.3390/nano12020259.
Повний текст джерелаАнотація:
The synthesis and characterization of multicolor light-emitting nanomaterials based on rare earths (RE3+) are of great importance due to their possible use in optoelectronic devices, such as LEDs or displays. In the present work, oxyfluoride glass-ceramics containing BaF2 nanocrystals co-doped with Tb3+, Eu3+ ions were fabricated from amorphous xerogels at 350 °C. The analysis of the thermal behavior of fabricated xerogels was performed using TG/DSC measurements (thermogravimetry (TG), differential scanning calorimetry (DSC)). The crystallization of BaF2 phase at the nanoscale was confirmed by X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM), and the changes in silicate sol–gel host were determined by attenuated total reflectance infrared (ATR-IR) spectroscopy. The luminescent characterization of prepared sol–gel materials was carried out by excitation and emission spectra along with decay analysis from the 5D4 level of Tb3+. As a result, the visible light according to the electronic transitions of Tb3+ (5D4 → 7FJ (J = 6–3)) and Eu3+ (5D0 → 7FJ (J = 0–4)) was recorded. It was also observed that co-doping with Eu3+ caused the shortening in decay times of the 5D4 state from 1.11 ms to 0.88 ms (for xerogels) and from 6.56 ms to 4.06 ms (for glass-ceramics). Thus, based on lifetime values, the Tb3+/Eu3+ energy transfer (ET) efficiencies were estimated to be almost 21% for xerogels and 38% for nano-glass-ceramics. Therefore, such materials could be successfully predisposed for laser technologies, spectral converters, and three-dimensional displays.
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Quinet, Pascal, and Patrick Palmeri. "Current Status and Developments of the Atomic Database on Rare-Earths at Mons University (DREAM)." Atoms 8, no. 2 (May 2, 2020): 18. http://dx.doi.org/10.3390/atoms8020018.
Повний текст джерелаАнотація:
The main purpose of the Database on Rare Earths At Mons University (DREAM) is to provide the scientific community with updated spectroscopic parameters related to lanthanide atoms (Z = 57–71) in their lowest ionization stages. The radiative parameters (oscillator strengths and transitions probabilities) listed in the database have been obtained over the past 20 years by the Atomic Physics and Astrophysics group of Mons University, Belgium, thanks to a systematic and extensive use of the pseudo-relativistic Hartree-Fock (HFR) method modified for taking core-polarization and core-penetration effects into account. Most of these theoretical results have been validated by the good agreement obtained when comparing computed radiative lifetimes and accurate experimental values measured by the time-resolved laser-induced fluorescence technique. In the present paper, we report on the current status and developments of the database that gathers radiative parameters for more than 72,000 spectral lines in neutral, singly-, doubly-, and triply-ionized lanthanides.
Дисертації з теми "Laser, Rare-earths, Spectroscopy"
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Damiano, Eugenio. "Tunable Solid-State Lasers Based on Rare-Earth-Doped Fluoride Single Crystals." Doctoral thesis, Università di Siena, 2019. http://hdl.handle.net/11365/1087623.
Повний текст джерелаАнотація:
Rare-earth-doped fuorides single crystals have been proven to be reliable and interesting active media for solid-state lasers (SSLs) . In particular, they possess long spectral lifetimes, narrow emission linewidths and the high-quality output beams. These features allow them to compete both with semiconduc- tor laser and solid-state lasers based on other insulating materials and also to achieve laser emission in previously uncovered wavelength regions. In this work I report on the developement of SSLs in the visible, and in the near infrared region around 2 m. Fluoride crystals doped with thulium or co-doped with thulium and holmium can be pumped with laser diode near 800 nm to achieve ecient laser emission in the range 1.8-2.1 m. Thanks to the peculiar absorption properties of wa- ter and atmospheric gases in this region, these sources can be used for laser scalpels, surveillance, long-range LIDARs, and gas detection in the atmosphere. We investigated the spectroscopic, laser properties and tunability of two cu- bic materials, SrF2 doped with thulium (Tm:SrF2) and KY3F10, doped with thulium (Tm:KYF) or co-doped (Tm-Ho:KYF). For the single doped we ob- tained maximum slope eciencies of 67% and 56% respectively, and tunability of 180 nm and 194 nm. In the co-doped sample, we obtained a slope eciency of 24% and a tunability of 61 nm around 2.1 m. In the visible part of the spectrum, compact and reliable laser sources in the deep red region are nowadays required to pump strontium atomic lattice clocks, to reduce the size and complexity of the system for space-oriented applications. We studied the laser capabilities of two dierent hosts: Pr3+:Ba(Y(1x)Lux)2F8 (Pr:BYLF) and Pr3+:LiGdF4 (Pr:GLF). In both we observed tunability around 698 nm clock transition". In Pr:GLF we achieved continuous-wave laser emis- sion at 674, 688, 689, 698, and 707 nm, thus covering all the deep-red wave- lengths required for Sr0 clocks and the clock transition" of Sr+. These results provide the basis for the development of a compact and long-lasting laser plat- form for strontium metrology, based on diode-pumped solid-state lasers. Moreover we demonstrated the potential of praseodymium-doped single- crystal bers (SCFs) as compact and cost-ecient active media for visible lasers, by obtaining for the rst time laser emission in Pr:LiYF4 (Pr:YLF) and Pr:KYF SCFs . These bers were grown using thr relatively new technique of micro- pulling-down, which was proven to be a valid alternative to the 'more traditional' Czochralski method for the growth of monocrystalline laser materials.
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JAKUTIS, NETO JONAS. "Laser de fibra monocristalina de fluoretos e caracterização de fibras dopadas com terras raras." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11691.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP
FAPESP:06/52788-7
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Senanayake, Pubudu Seewali. "Two-Colour Excitation of Impurity Trapped Excitons in Wide Bandgap Insulators." Thesis, University of Canterbury. Department of Physics and Astronomy, 2013. http://hdl.handle.net/10092/8710.
Повний текст джерелаАнотація:
Impurity trapped excitons (ITEs) occurring in divalent ytterbium doped calcium and strontium fluoride crystals have been investigated by exploiting the radically different radiative decay rates of the lowest exciton state and higher excited states, utilizing a novel two-colour transient photoluminescence enhancement experiment. The ITE energy levels have been directly measured with the observation of sharp transitions occurring from the changes of states of the localized hole and broad bands associated with changes of state of the delocalized electrons. The dynamic behaviour under excitation by time delayed ultra-violet (UV) and infrared (IR) pulses has been observed allowing for the identification of excitation and decay pathways between the ITE states.
The position and transition intensities of the sharp lines within the IR excitation spectrum have been successfully matched using a semi-empirical effective Hamiltonian crystal field
model. In CaCaF₂:Yb²⁺ the lines occurring at 249 and 1145 cm⁻¹ were matched with the crystal field parameter B4 = 800 cm⁻¹ and the exchange parameter G3(fs) = 5900 cm⁻¹. In SrCaF₂:Yb²⁺ these lines were observed at 178 and 1284 cm⁻¹ and matched with B4 = 600 cm⁻¹ and G3(fs) = 7278 cm⁻¹. Local heating and direct absorption by intra-excitonic transitions are found to be the causes of the broad band observed in the spectrum and have been deconvolved by studying the dynamic behaviour of the monitored emission at different IR excitation frequencies. Through this modeling, higher lying ITE states have been identified occurring at 785 cm⁻¹ in SrCaF₂:Yb²⁺ and in between 740 - 820 cm⁻¹ in CaCaF₂:Yb²⁺.
The dynamic model developed successfully simulates the temporal behaviour of the emission under IR excitation under a variety of parameters including IR fluence, excitation frequency, sample temperature and UV - IR pulse delay. Examination of the SrCaF₂:Yb²⁺ dynamic behaviour over a time scale of 100 ms shows UV driven trap population at a rate of approximately 3% per pulse, which are liberated and recycled to the Yb²⁺ ground state by the IR pulse. The two-colour technique is applied to MgCaF₂:Yb²⁺, a candidate for possible ITE emission. Temperature dependent emission spectra obtained under UV excitation indicates the possibility of an ITE state, independently populated from the 5d level of the Yb²⁺. Typical
5d emission is also observed from this system. Under IR excitation, liberation of shallow traps and possible local heating is observed. No ITE emission is conclusively found with IR probing.
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Normani, Simone. "Nd Lu CaF2 for high-energy lasers." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC230/document.
Повний текст джерелаАнотація:
La possibilité d’obtenir une émission laser efficace sur une large bande spectrale autour de 1.05 µm a été démontrée récemment en utilisant des monocristaux CaF2 and SrF2 dopés Nd3+. Cette émission, éteinte du fait de la relaxation croisée entre ions dans les matériaux de type fluorite, peut être exaltée avec l’insertion d’ions “tampons” comme Y3+ ou Lu3+. Une émission laser accordable sur une large bande spectrale et la génération d’impulsions ultracourtes sont donc possibles. De plus, ce type de matériau est particulièrement intéressant pour des amplificateurs de forte puissance pompés par diodes. Une étude complète des propriétés spectrales et thermomécaniques de cristaux de CaF2:Nd3+ co-dopés avec des concentrations variables de Lu3+ a été menée en collaboration avec le CEA CESTA au sein du projet LASCAN pour de futurs développements au sein du Laser MégaJoule (LMJ) avec pour but l’amélioration des performances des amplificateurs pilotes. L’effet d’élimination des clusters de Nd3+ par le co-dopage avec le Lu3+ et l’apparition de deux sites actifs différents a été mise en évidence et caractérisée en détail. Ce travail présente ainsi une spectroscopie complète des centres actifs dans CaF2:Nd3+,Lu3+, une étude des propriétés thermomécaniques, ainsi que des propriétés d’amplification optique des matériaux étudiésIt was recently demonstrated that efficient and broadband laser emission was possible with Nd-doped CaF2 and SrF2 single crystals around 1.05 µm. Such laser emission, known as completely quenched because of cross-relaxation in the singly doped fluorites, increases spectacularly by co-doping with non-optically active “buffer” ions like Y3+ or Lu3+. Broadband laser emission and ultra-short laser operation are therefore possible. The material is particularly appealing for large scale high peak power diode-pumped amplifiers. A deep investigation of the spectral properties of CaF2:Nd3+ crystals co-doped with various amounts of Lu3+ was performed. The cluster breaking effect of Lu3+ codoping has as a side-effect the appearance of two different contributions, identified as two different active sites, which is in agreement with recent observations. In this work, we investigate in depth the different centres’ spectroscopic properties and operational parameters for laser applications,their evolution as the lutetium concentration increases, and the thermomechanical properties of said samples. A preliminary investigation on the amplification properties and laser operation of said materials is performed as well
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JAGOSICH, FABIO H. "Estudos espectroscopicos para o desenvolvimento dos meios laser ativos de Ho sup [3+] e Er sup [3+] no YLF que operam na regiao de 3 microns." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10805.
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FAPESP:97/10816-3
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RANIERI, IZILDA M. "Crescimento de cristais de LiY sub(1-x) TR sub(x) F sub(4):Nd (TR=Lu ou Gd) para aplicacoes opticas." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10935.
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COURROL, LILIA C. "Estudo quantitativo da luminescencia do Hosup3+ em cristais de YLF e HoLF e analise da dinamica dos processos de transferencia de energia do Ybsup3+ para os ions de Tmsup3+ e Hosup3+ em cristais." reponame:Repositório Institucional do IPEN, 1994. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10388.
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Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Barbier, Sophie. "Étude des techniques de spectrométrie de plasma pour l'analyse de matériaux à spectres optiques complexes : application aux terres rares et aux matériaux plastiques." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10279/document.
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La LIBS (Laser Induced Breakdown Spectroscopy) est une technique d'analyse élémentaire basée sur l'exploitation du spectre d'émission optique issu de l'ablation laser d'un échantillon. Aujourd'hui, la LIBS ne s'est pas encore imposée comme une technique de choix pour la majorité des applications comme c'est le cas pour les techniques de plasma à couplage inductif. L'une des principales raisons à cela est la difficulté à fournir des mesures quantitatives justes. Il existe donc aujourd'hui une nécessité de mieux comprendre et caractériser les plasmas et les phénomènes issus de l'interaction laser-Matière sur tout type de matériaux pour améliorer les performances de cette technique analytique. Cette interaction laser/matière étant, de plus, spécifique au type de matériau analysé, il est indispensable d'étudier ces effets sur une vaste gamme de matériaux. Deux types d'échantillons ont donc été utilisés pour étudier les plasmas LIBS: des matériaux contenant des terres rares et des matériaux plastiques. Les travaux réalisés sur les terres rares ont permis de sélectionner des raies d'analyse « disponibles », c'est-À-Dire sans interférences spectrales provenant des autres éléments de cette famille et suffisamment sensibles pour réaliser une analyse quantitative. Cette étude a mis en avant le fait que les effets de matrice dus à la quantité de terres rares et à la nature de l'échantillon sont importants. Ces effets de matrice sont propres à chaque élément et à chaque matrice, ils sont donc à prendre en considération pour toute analyse LIBS d'un échantillon contenant plusieurs terres rares. Si l'accumulation d'un grand nombre de terres rares a un effet significatif sur le signal d'un de ces analytes, leurs présences en nombre et quantité limitée (2 à 4) donnent un effet compensable par étalonnage interne. Dans le cadre de l'analyse LIBS des matériaux plastiques, une étude détaillée du signal en utilisant différentes conditions de plasma a été réalisée. L'analyse quantitative s'est portée sur plusieurs éléments dont certains difficiles à exciter comme le brome et le chlore. Grâce à l'utilisation d'une atmosphère contrôlée d'hélium, la détection des halogènes employés comme retardateurs de flamme dans les plastiques, a été possible. Un important effet de matrice a été observé à 266 nm en comparaison avec les résultats obtenus à 532 nm. Cependant, ces différences marquées à 266 nm ont permis la discrimination des quatre familles de polymères étudiées. En présence d'hélium, des différences significatives ont été obtenues pour les rapports C2/He et CN/He. En les traçant l'un en fonction de l'autre, il est ainsi possible de discriminer les différents types de plastiques étudiésThe LIBS (Laser Induced Breakdown Spectroscopy) technique is an elemental analysis technique based on the use of the optical emission spectrum from a sample of laser ablation. Today, LIBS has not emerged as a technique of choice for the majority of applications, as is the case for inductive coupled plasma techniques. One of the main reasons for this is the difficulty in providing accurate quantitative measurements. So there is now a need to better understand and characterize plasmas and phenomena from laser-Matter interaction on all types of materials to improve the performance of this analytical technique. This laser/material interaction is specific to the type of material analyzed, so it is essential to study these effects on a wide range of materials. Two types of samples have been used to study LIBS plasmas: materials containing rare earths and plastics. Work on rare earths were used to select the analytical lines free of spectral interference from other elements of this family and sensitive enough to carry out a quantitative analysis. This study highlighted the fact that the matrix effects due to the amount of rare earth and nature of the sample are important. These matrix effects are unique to each element and matrix, so they are to be considered in all LIBS analysis of a sample containing several rare earths. If the accumulation of a large number of rare earths (i.e 12) has a significant effect on the signal of the analytes, the effect of a limited number (i.e. 2 to 4) could be compensated by use on an internal standard. In the context of the LIBS analysis of plastic materials, a detailed study of the signal using different plasma conditions was performed. The quantitative analysis was focused on several elements, including bromine and chlorine which are difficult to excite. Through the use of a controlled atmosphere of helium, the detection of halogens used as flame retardants in plastics was significantly improved. An important matrix effect was observed at 266 nm in comparison with the results obtained at 532 nm. However, these differences at 266 nm allowed the discrimination of four families of polymers studied. In the presence of helium, significant differences were obtained for the C2 / He and CN / He ratios. This criteria was found to be relevant for the discrimination between the different types of plastics studied
Книги з теми "Laser, Rare-earths, Spectroscopy"
1
Guokui, Liu, and Jacquier Bernard, eds. Spectroscopic properties of rare earths in optical materials. Berlin: Springer, 2005.
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2
Tremblay, Mario Elmen. Laser-excited ionic fluorescence of the rare earths in the inductively coupled plasma. 1987.
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3
Liu, Guokui, and Bernard Jacquier. Spectroscopic Properties of Rare Earths in Optical Materials. Springer Berlin / Heidelberg, 2010.
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4
(Editor), Guokui Liu, and Bernard Jacquier (Editor), eds. Spectroscopic Properties of Rare Earths in Optical Materials (Springer Series in Materials Science) (Springer Series in Materials Science). Springer, 2005.
Знайти повний текст джерелаЧастини книг з теми "Laser, Rare-earths, Spectroscopy"
1
Moncorgé, R. "Current Topics in Rare-earth Lasers." In Spectroscopic Properties of Rare Earths in Optical Materials, 320–78. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/3-540-28209-2_6.
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2
Jacquier, B., L. Bigot, S. Guy, and A. M. Jurdyc. "Rare Earth Doped Confined Structures for Lasers and Amplifiers." In Spectroscopic Properties of Rare Earths in Optical Materials, 430–61. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/3-540-28209-2_8.
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3
Yen, William M. "Chapter 87 Lase spectroscopy." In Handbook on the Physics and Chemistry of Rare Earths Volume 12, 433–77. Elsevier, 1989. http://dx.doi.org/10.1016/s0168-1273(89)12011-x.
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