978 resultados para Er^3


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Phosphoniobate glasses with composition (mol%) (100-x) NaPO(3)-xNb(2)O(5) ( x varying from 11 to 33) were prepared and characterized by means of thermal analysis, Fourier transform infrared spectroscopy, Raman scattering and (31)P nuclear magnetic resonance. The addition of Nb(2)O(5) to the polyphosphate base glass leads to depolymerization of the metaphosphate structure. Different colors were observed and assigned as indicating the presence of Nb(4+) ions, as confirmed by electron paramagnetic resonance measurements. The color was observed to depend on the glass composition and melting temperature as well. Er(3+) containing samples were also prepared. Strong emission in the 1550 nm region was observed. The Er(3+4)I(15/2) emission quantum efficiency was observed to be 90% and the quenching concentration was observed to be 1.1 mol%( 1.45 x 10(20) ions cm(-3)). Planar waveguides were prepared by Na(+)-K(+)-Ag(+) ion exchange with Er(3+) containing samples. Optical parameters of the waveguides were measured at 632.8, 543.5 and 1550 nm by the prism coupling technique as a function of the ion exchange time and Ag(+) concentration. The optimized planar waveguides show a diffusion depth of 5.9 mu m and one propagating mode at 1550 nm.

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Coordenao de Aperfeioamento de Pessoal de Nvel Superior (CAPES)

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In rare earth ion doped solids, a resonant non-linear refractive index, n2, appears when the laser pumps one of the ion excited states and the refractive index change is proportional to the excited state population. In these solids there are usually thermal and non-thermal lensing effects, where the non-thermal one is due to the polarizability difference, , between excited and ground states of the ions. We have used the time resolved Z-scan and a mode-mismatched thermal lens technique with an Ar+ ion laser in Er+3 (20ZnF2-20SrF2-2NaF-16BaF2-6GaF3-(36 - x)InF3-xErF3, with x= 1, 2, 3 and 4 mol%) and Nd+3 (20SrF2-16BaF2-20ZnF2-2GdF3-2NaF-(40 - x)InF3-xNdF3, with x = 0.1, 0.25, 0.5-1 mol%) doped fluoroindate glasses. In both samples we found that the non-linear refraction is due to the thermal effect, while the non-thermal effect is negligible. This result indicates that in fluoride glasses is very small (less than 10-26 cm3). We also measured the imaginary part of the non-linear refractive index (n2) due to absorption saturation.

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Relative to the Er3 +:gold-nanoparticle (Er3 +:Au-NP) axis, the polarization of the gold nanoparticle can be longitudinal (electric dipole parallel to the Er3 +:Au-NP axis) or transverse (electric dipole perpendicular to the Er3 +:Au-NP axis). For longitudinal polarization, the plasmon resonance modes of gold nanoparticles embedded in Er3 +-doped germanium-tellurite glass are activated using laser lines at 808 and 488 nm in resonance with radiative transitions of Er3 + ions. The gold nanoparticles were grown within the host glass by thermal annealing over various lengths of time, achieving diameters lower than 1.6 nm. The resonance wavelengths, determined theoretically and experimentally, are 770 and 800 nm. The absorption wavelength of nanoparticles was determined by using the Frohlich condition. Gold nanoparticles provide tunable emission resulting in a large enhancement for the 2H11/2 4I13/2 (emission at 805 nm) and 4S 3/2 4I13/2 (emission at 840 nm) electronic transitions of Er3 + ions; this is associated with the quantum yield of the energy transfer process. The excitation pathways, up-conversion and luminescence spectra of Er3 + ions are described through simplified energy level diagrams. We observed that up-conversion is favored by the excited-state absorption due to the presence of the gold nanoparticles coupled with the Er3 + ions within the glass matrix. 2013 Elsevier B.V.

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MoSb_2O_5R_2O_3R'_2O_3Bi_2O_3Bi~(3+)ThorntonBa_2BiSbO_6Ba_2GdSbO_6EECEHKOM_2RSbO_6 (M = BaSrCa, R = La Y)M_2RSbO_6Sm~(3+)Eu~(3+)Dy~(3+)Ho~(3+)Er~(3+)Tm~(3+)Bi~(3+)Bi~(3+)X-M_2RSbO_6(M = BaSrR = LaYGdBi)Fm3mOhCa_2YSbO_6P_(21)M_2RSbO_6 (M = BaSrCa; R = GdYBi)Ba_2GdSbO_6Sb_2O_5M_2RSbO_6Sb_2O_3520 Sb_2O_5Eu~(3+)Ba_2YSbO_6:Eu~(3+)Br_2YSbO_6:Eu~(3+), Bi~(3+)254nmEu~(3+)595nmBi~(3+)325nmBi~(3+)Eu~(3+)Eu~(3+)595nmBi~(3+)Eu~(3+)Bi~(3+)~1S 3P_1Eu~(3+)~5D_0~5D_0 7F_1Eu~(3+)Sr_2YSbO_6:Eu~(3+)Sr_2YSbO_6:Eu~(3+), Bi~(3+)245nmEu~(3+)595nmBi~(3+)335nmBi~(3+)Eu~(3+)Ba_2YSbO_6:Eu~(3+)Ba_2YSbO_6:Eu~(3+), Bi~(3+)Eu~(3+)Ca_2YSbO_6:Eu~(3+)Ca_2YSbO_6:Eu~(3+), Bi~(3+)396nmEu~(3+)613nmBi~(3+)313nmBi~(3+)Eu~(3+)Bi~(3+)3P_1 ~1S_0400nmEu~(3+)~7F_0 ~5L_6396nm~5L_6~5D_0~7F_2Ca_2Y_(0.96)Eu_(0.04)SbO_6Eu~(3+)Eu~(3+)Fm3m Ba_2YSbO_6Sr_2YSbO_6Oh~5D_0 ~7F_1Eu~(3+)P_(21)~5D_0 ~7F_2M_2YSbO_6:R~(13+)(M = BaCa; R' = SmDyHoErTm)Sm~(3+)Dy~(3+)Ho~(3+)Bi~(3+)Ca_2YSbO_6:Bi~(3+)Bi~(3+)240nm~1S_0 ~1P_1315nm~1S_0 ~3P_1400nm~3P_1 ~1S_0

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YAG phosphor powders doped/codoped with Er(3+)/(Er(3+) + Yb(3+)) have been synthesised by using the solution combustion method. The effect of direct pumping into the (4)I(11/2) level under 980 nm excitation of doped/codoped Er(3+)/Yb(3+)-Er(3+) in Y(3)Al(5)O(12) (YAG) phosphor responsible for an infrared (IR) emission peaking at similar to 1.53 mu m corresponding to the (4)I(13/2)->(4)I(15/2) transition has been studied. YAG exhibits three thermally-stimulated luminescence (TSL) peaks at around 140A degrees C, 210A degrees C and 445A degrees C. Electron spin resonance (ESR) studies were carried out to identify the centres responsible for the TSL peaks. The room temperature ESR spectrum of irradiated phosphor appears to be a superposition of two distinct centres. One of the centres (centre I) with principal g-value 2.0176 is identified as O(-) ion, while centre II with an isotropic g-factor 2.0020 is assigned to an F(+) centre (singly ionised oxygen vacancy). An additional defect centre is observed during thermal-annealing experiments and this centre (assigned to F(+) centre) seems to originate from an F-centre (oxygen vacancy with two electrons) and these two centres appear to correlate with the observed high-temperature TSL peak in YAG phosphor.

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Er(3+) doped Y(2)O(3) phosphor was prepared by the solution combustion method and characterized using powder x-ray diffraction and energy-dispersive analysis of x-ray mapping studies. Room temperature near infrared (NIR) to green up-conversion (UC) emissions in the region 520-580 nm {((2)H(11/2), (4)S(3/2)) -> (4)I(15/2)} and red UC emissions in the region 650-700 nm ((4)F(9/2) -> (4)I(15/2)) of Er(3+) ions have been observed upon direct excitation to the (4)I(11/2) level using similar to 972 nm laser radiation of nanosecond pulses. The possible mechanisms for the UC processes have been discussed on the basis of the energy level scheme, the pump power dependence as well as based on the temporal evolution. The excited state absorption is observed to be the dominant mechanism for the UC process. Y(2)O(3) : Er exhibits one thermally stimulated luminescence (TSL) peak around 367 degrees C. Electron spin resonance (ESR) studies were carried out to study the defect centres induced in the phosphor by gamma irradiation and also to identify the centres responsible for the TSL peak. Room temperature ESR spectrum of irradiated phosphor appears to be a superposition of at least three distinct centres. One of them (centre I) with principal g-values g(parallel to) = 2.0415 and g(perpendicular to) = 2.0056 is identified as O(2)(-) centre while centre II with an isotropic g-factor 2.0096 is assigned to an F(+)-centre (singly ionized oxygen vacancy). Centre III is also assigned to an F(+)-centre with a small g-factor anisotropy (g(parallel to) = 1.974 and g(perpendicular to) = 1.967). Additional defect centres are observed during thermal annealing experiments and one of them appearing around 330 degrees C grows with the annealing temperature. This centre (assigned to an F(+)-centre) seems to originate from an F-centre (oxygen vacancy with two electrons) and the F-centre appears to correlate with the observed TSL peak in Y2O3 : Er phosphor. The trap depth for this peak has been determined to be 0.97 eV from TSL data.

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This paper presents the characterization of single-mode waveguides for 980 and 1550 nm wavelengths. High quality planar waveguide structure was fabricated from Y(1-x)Er(x)Al(3)(BO(3))(4) multilayer thin films with x = 0.02, 0.05, 0.1, 0.3, and 0.5, prepared through the polymeric precursor and sol-gel methods using spin-coating. The propagation losses of the planar waveguides varying from 0.63 to 0.88 dB/cm were measured at 632.8 and 1550 nm. The photoluminescence spectra and radiative lifetimes of the Er(3+) (4)I(13/2) energy level were measured in waveguiding geometry. For most samples the photoluminescence decay was single exponential with lifetimes in between 640 mu s and 200 mu s, depending on the erbium concentration and synthesis method. These results indicate that Er doped YAl(3)(BO(3))(4) compounds are promising for low loss waveguides. (C) 2009 Elsevier B.V. All fights reserved.

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We report a Raman study of single crystal pyrochlore Er(2)Ti(2)O(7) as a function of temperature from 12 to 300 K. In addition to the phonons, various photoluminescence (PL) lines of Er(3+) in the visible range are also observed. Our Raman data show an anomalous red-shift of two phonons (one at similar to 200 cm(-1) and another at similar to 520 cm(-1)) upon cooling from room temperature which is attributed to phonon-phonon anharmonic interactions. However, the phonons at similar to 310, 330, and 690 cm(-1) initially show a blue-shift upon cooling from room temperature down to about 130 K, followed by a red-shift, indicating a structural deformation at similar to 130 K. The intensities of the PL bands associated with the transitions between the various levels of the ground state manifold ((4)I(15/2)) and the (2)H(11/2) as well as (4)S(3/2) excited state manifolds of Er(3+) show a change at similar to 130 K. Moreover, the temperature dependence of the peak position of the two PL bands shows a change in their slope (d(omega)/d(T)) at similar to 130 K, thus further strengthening the proposal of a structural deformation. The temperature dependence of the peak positions of the PL bands has been analyzed using the theory of optical dephasing in crystals.

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N_2-H_2M_2~ICO_3 + M_3~(II)(PO_4)_2 + M_2~(III)O_3 + (NH_4)_2HPO_4 + M~(II)F_2 M_x~IM_(10-2x)~(II)M_x~(III)(PO_4)_6F_2 + NH_3 + H_2OM~I = Li~+, Na~+, K~+; M~(II) = Ca~(2+), Sr~(2+); M~(III) = Y~(3+), La~(3+), Gd~(3+); X = 0.5, 1, 2, 3XEu~(3+)M_(10)~(II)(PO_4)_6F_2(Pb_3/m)ac9.416.89 AM~I, M~(II)M~(III)XCe~(3+)Na_2Ca_6La_2(PO_4)_6F_2Ce~(3+)Ce~(3+)-Mn~(2+), Ce~(3+)-Re~(3+) (Re~(3+) = Pr~(3+)Nd~(3+)Sm~(3+)Tb~(3+)Dy~(3+)Tm~(3+)Ho~(3+)Er~(3+))Ce~(3+)-Mn~(2+)-Re~(3+) (Re~(3+) = Dy~(3+), Nd~(3+))Na_2Ca_6La_2(PO_4)_6F_2:Ce~(3+)338358nm~2D-~2F_(5/2)~2D-~2F_(1/2)~2D-~2F_(6/2)~2D-~2F_(7/2)Ce~(3+)F~-Ce~(3+)-Ce~(3+)Ce~(3+)Mn~(2+)Ce~(3+)Re~(3+)A. Ce~(3+)-Sm~(3+)Tb~(3+)Dy~(3+)Tm~(3+)BCe~(3+)-Nd~(3+)Pr~(3+)C. Ce~(3+)-Ho~(3+), Er~(3+)ABCe~(3+)(_T)_A > (_T)_BCe~(3+)-Ho~(3+)Ce~(3+)-Er~(3+)Ho~(3+)Er~(3+)Ce~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)Ce~(3+)Mn~(2+)Re~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)Ce~(3+)-Mn~(2+)Ce~(3+)-Re~(3+)Ce~(3+)-Mn~(2+)-Re~(3+)M. YokataCe~(3+)Ce~(3+)-Mn~(2+)Ce~(3+)-ReCe~(3+)-Mn~(2+))-Re~(3+)Ce~(3+)Ce~(3+)Ce~(3+)(_f, _R)

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1234N_(1923)Zn(II)Cd(II)Re(III)N_(1923)ZnCl_2CdCl_2Zn(SCN)_2N_(1923)HPMBPREIIIN_(1923)Sc(III)N_(1923)(TBP, DBBP)Zn(II)Cd(II)1. N_(1923)TBPDBBPZnCl_2 N_(1923)TBPDBBPZnCl_2(RNH_3Cl)_3ZnCl_2B(RNH_3Cl)_2ZnCl_2B (B = TBPDBBP)ZnCl_2 + (RNH_3Cl)_3_((o)) + TBP_((o)) ~(K_(12)(TBP) (RNH_3Cl)_3ZnCl_3ZnCl_2TBP_((o)) ZnCl_2+Z/3(RNH_3Cl)_(3(o)) + DBBP_((o)) (RNH_3Cl)_2 ZnCl_2DBBP_((o))(RNH_3Cl)_3ZnCl_(2(o)) + TBP_((o))~(B_(12)(TBP) (RNH_3Cl)_3ZnCl_2TBP_((o)) (RNH_3Cl)_3ZnCl_(2(o)) + DBBP_((o)) ~(B_(12)(DBBP) (RNH_3Cl)_2ZnCl_2DBBP_((o)) + RNH_3Cl_((o))Zn(II)DBBP>TBPDD_1/DD_IRNMR2.N_(1923)TBPZn_(SCN)_2N_(1923)TBPZn(SCN)_2TBPZn(SCN)_2N_(1923)TBPZn(SCN)_2Zn(SCN)_23TBP. (RNH_3)_2Zn(SCN)_4TBP,Zn(SCN)_4~(2-) + (RNH_3NO_3)_(2(o)) + TBP_((o)) (RNH_3)_2Zn(SCN)_4TBP_((o)) + 2NO_3~-(RNH_3)_2Zn(SCN)_(4(o)) + TBP_((o)) ~(B'12) (RNH_3)_2Zn(SCN)_4TBP_((o)) (a) (RNH_3NO_3)_(2(o)) + Zn(SCN)_23TBP_((o)) + 2SCN~-~("12)(RNH_3)Zn(SCN)_4TBP_((o))+2TBP_((o))+2NO_3~- (b) (RNH_3NO_3)_(2(o)) + (RNH_3)_2Zn(SCN)_(4(o)) + 2SCN~- + Zn(SCN)_2.3TBP_((o)) ~("12)R(RNH_3)_2Zn(SCN)_4.TBP_((o)) + 2NO_3~- + TBP_((o)) (c) "'_(12) > '_(12) > "_(12)cabSCN~- > Cl~_IR3. N_(1923)TBPDBBPCdIIN_(1923)TBPDBBPCd(II)(RNH_3Cl)_2CdCl_2BCdCl_2 + 2/3 (RNH_3Cl)_(3(o)) + B_((o)) ~(K_(12)) (RNH_3Cl)_2CdCl_2B_((o)) (RNH_3Cl_3)CdCl_2_((o)) + B_((o)) ~(BR)(RNH_3Cl)_2CdCl_2B_((o)) + RNH_3Cl_((o))Zn(II)Zn(II) > Cd(II)IRNMR. N_(1923)HPMBPREIIIN_(1923)HPMBPREIIIRE~(3+ = La~(3+), Pr~(3+), Eu~(3+), Gd~(3+), Tb~(3+), Er~(3+), Yb~(3+)Y~(3+)RNH_3Ln(PMBP)_4Pr(III)Ln~(3+) + 4HPMBP_((o)) + RNH_3Cl_((o)) RNH_3LN(PMBP)_(4(o)) + 4H~+ + Cl~- Ln(PMBP)_(3(o)) + RNH_3Cl_((o)) RNH_3Ln(PMBP)_(4(o)) + H~+ + Cl~- RZRNH_3ClPr(III)IRNMRN_(1923)Sc(III)RNH_3NO_3Sc(III)Sc(OH)_2~+SCN~-, NO_3~-RNH_3nO_3Sc(III)PHSc(OH)_2~+ + SCN~- + 2(RNH_3NO_3)_(2((o)) (RNH_3nO_3)_4.Sc(OH)_2SCN_((o)) Sc(OH)_2~+ + SCN~- + NO_3~- + (RNH_3NO_3)_(2(o)) (RNH_3NO_3)_2.Sc(OH)(SCN)NO_3 + OH~-

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Er-doped silicon-rich silicon nitride (SRN) films were deposited on silicon substrate by an RF magnetron reaction sputtering system. After high temperature annealing, the films show intense photoluminescence in both the visible and infrared regions. Besides broad-band luminescence centered at 780 nm which originates from silicon nanocrystals, resolved peaks due to transitions from all high energy levels up to ~2H_(11/2) to the ground state of Er~(3+) are observed. Raman spectra and HRTEM measurements have been performed to investigate the structure of the films, and possible excitation processes are discussed.

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InPGaAsSi7101411015cm2Er, PL, Er315m, InP, Er3ErSi, InP, ErInPSi712

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f-f,-(Ferron,7-8-5-),,Ln~(3+)(Pr~(3+)Nd~(3+)Er~(3+))-Ferron,f-f,,

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YAG:ErEr~(3+),Er~(3+)(~4S_(3/2),~4F_(9/2)~2H_(11/2)),~4I_(11/2)I_(13/2)