Spectra Of Yb3 Research Articles

Yb,Ho,Pr:GYTO晶体生长、结构及光谱性能（特邀）

A new mid infrared laser material Yb,Ho,Pr:GYTO crystal was grown successfully using Czochralski method for the first time. The structural parameters were obtained by the X-ray Rietveld refinement method. The X-ray rocking curves of the (100), (010), and (001) diffraction face of Yb,Ho,Pr:GYTO crystal were measured. The full widths at half maximum of those diffraction peaks are 0.036°, 0.013°, and 0.077°, respectively, which indicates a high crystalline quality of the as-grown crystal. Laser Ablation Inductively-Coupled Plasma Mass Spectrometry was used to measure the concentrations of Yb3+, Ho3+, Pr3+, and Y3+ ions in the Yb,Ho,Pr:GdYTaO4 crystal. The effective segregation coefficients of Yb3+, Ho3+, Pr3+, and Y3+ in Yb,Ho,Pr:GYTO crystal are 0.624, 1.220, 1.350, and 0.977, respectively. The room-temperature polarhosized absorption spectra of Yb,Ho,Pr:GdYTaO4 was measured and the corresponding absorption transitions were assigned. The 2.9 μm fluorescence spectrum excited by 940 nm LD presents that the strongest emission is located at 2908 nm. In addition, the Yb-Ho-Pr energy transfer mechanism in GYTO was also demonstrated. Compared with Ho:GYTO crystal, the lifetime of 5I7 level of Yb,Ho,Pr:GYTO crystal is reduced by 87.13%, which is close to that of the upper level 5I6, indicating that Yb,Ho,Pr:GYTO crystal is easier to realize population inversion and laser output.

Upconversion color tunability and white light generation in Yb3+/Er3+/Tm3+ tri-doped CaF2 single crystals

Yb3+/Er3+/Tm3+ tri-doped CaF2 single crystals have been successfully synthesized via Temperature Gradient Technique (TGT) method, and represented by X-ray diffraction (XRD) examination, absorption and fluorescence spectrum, pump power dependence and lifetime analysis in details. Under the excitation of 980 nm laser diode (LD), the upconversion luminescence (UCL) spectra of Yb3+/Er3+/Tm3+/CaF2 as a function of Tm3+ concentration are made up of intense blue (Tm3+:1G4 → 3H6), green (Er3+: 4S3/2, 2H11/2 → 4I15/2), and red (Er3+:4F9/2 → 4I15/2) emissions, which are located at 478, 523, 539 and 656 nm, respectively. With increasing concentration of Tm, the color can be tunable from orange-yellow, white to blue light. And the optimal Yb3+/Er3+/Tm3+ doping concentrations for white light are determined to be 10%Yb, 0.1%Er and 0.05%Tm. The research indicates that the as-prepared materials may have potential applications in the fields of three dimensional displays, back lighting, white light sources, and so on.

Spectra properties of Yb3+, Er3+: Sc2SiO5 crystal**Project supported by the National Key Research and Development Program of China (Grant No. 2016YFB0701002), the Joint Fund of the National Natural Science Foundation of China and China Academy of Engineering Physics (NSAF) (Grant No. U1530152), the National Natural Science Foundation of China (Grant Nos. 91222112 and 61475177), and Shanghai Rising-Star Program (B type),

The influence of Er3+ ions on the spectra of Yb3+, Er3+: Sc2SiO5 (SSO) single crystal, which was obtained by Czochralski (Cz) method, is discussed. The absorption coefficient at 980 nm was 13.36 cm−1 with a peak absorption cross-section of 1.46 × 10−20 cm2. The emission cross-sections at 1034 nm and 1062 nm were 5.5 × 10−21 cm2 and 4.9 × 10−21 cm2, respectively. The fluorescence lifetime was estimated as 1.24 ms at 1061 nm. The mechanical properties of SSO single crystal were also presented.

Radiation Resistance of Yb:LaSc3(BO3)4 and Yb:LuYSiO5 Laser Crystals

The optical transmission (OT) spectra of Yb:LaSc3(BO3)4 and Yb:LuYSiO5 laser crystals have been analyzed before and after irradiation from a 60Co source with doses up to 45 Mrad. The OT spectra of the Yb:LuYSiO5 crystal are found to be the same (within the measurement error) before and after irradiation. The irradiation of the 10 at.%Yb:LaSc3(BO3)4 crystal significantly changes its OT spectra in a wide spectral range (330 to 700 nm). A 975-nm laser based on a previously irradiated 4 at.%Yb:LuYSiO5 crystal has exhibited a differential efficiency of 23% under diode pumping. The up-conversion luminescence spectra in the visible range of the crystals under study have been explained.

The experimental evidence of the amplified spontaneous emission of Yb3+ ions in LiYbF4 crystal

The experimental evidence of the amplified spontaneous emission of Yb3+ ions in LiYbF4 crystal, which partially stipulates up-conversion processes in Yb-sensitized phosphors, doped by rare-earth ions are presented for the first time. To do that the spatial distributions and the spectra of Yb3+ ions luminescence along the excitation radiation propagation through the sample were studied simultaneously. The laser diode radiation (1W, λ=932nm) was used for the luminescence excitation and its surface power density was varied by shifting of the position of the laser beam waist within the sample (similar to Z-scanning).

Optical Activity in the Near-IR Region: The λ=980 nm Multiplet of Chiral Yb3+ Complexes.

We used a very simplified electrostatic model based on charge and polarizability of atoms and groups on an organic ligand around a lanthanide ion to predict the near-infrared electronic circular dichroism (NIR ECD) spectra of Yb3+ (a monoelectronic ion). We tuned our method by using two widely different complexes. The first was the heterobimetallic species CsYb(hfbc)4 [hfbc=(-)-3-heptafluorobutyrylcamphorate], in which the ligand is a diketonate and, as such, is endowed with a chromophore with strong UV absorption (π-π* ). Its oxygen atoms define a square antiprism, which provides a symmetric coordination polyhedron. The second system was Yb DOTMA [DOTMA=(1R,4R,7R,10R)-α,α',α'',α'''-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid], a chiral Yb analogue of Gd DOTA (DOTA=1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), in which the ligand lacks relevant electronic transitions and provides a dissymmetric cage. The relative weights of dynamic (ligand polarization) and static contributions to Yb NIR ECD were evaluated, and the spectra appear to have been well predicted by theory through the introduction of a heuristic weight factor. To validate the approach and to confirm the value of the weight factor, we applied it to two other compounds, namely, Na3 Yb(BINOLate)3 and Yb(BINOLAM)3 [BINOLate=2,2'-dihydroxy-1,1'-binaphthyl; BINOLAM=3,3'-bis(diethylaminomethyl)-1-1'-bi-2-naphthol].

Study on LD-Pumped Yb:YAG Rod Laser

The physical properties and characteristics of absorption and emission spectra of Yb: YAG crystal are analyzed in this paper. From the rate equation of quasi-three-level system ,We derive the rate equations of diode-pumped continuous work-end-pumped solid state laser and a theoretical analysis and optimization design for continuous LD end-pumped lasers are given.

Influence of yttrium ions on the emission transfer features of Ce3+/Yb3+ co-doped lithium silicate glasses

Optical absorption and photoluminescence spectra (PL) of the glasses possessing compositions (49−x) Li2O−x Y2O3−50 SiO2:1.0 Ce2O3/1.0Yb2O3 and (49−x) Li2O−x Y2O3−50 SiO2:(0.5 Ce2O3+0.5 Yb2O3) with x varying from 5 to 15mol% were studied. The PL spectra of Ce3+ doped glasses excited at 360nm exhibited two broad parity allowed 5d(2D)→4f(2F5/2,7/2) bands in the blue spectral region, whereas the spectra of Yb3+ doped glasses excited at 900nm exhibited a broad emission band centered at about 980nm due to 2F5/2→2F7/2 transition. A significant enhancement in the intensity of NIR emission is observed due to the sensitization with Ce3+ ions. The increase in the rate of energy transfer from Ce3+ to Yb3+ could be observed with increasing Y2O3 content. The reasons for such improvement have been discussed within a framework of structural modifications taking place in the vicinity of Yb3+ ions.

CALCULATION OF THE PHOTOLUMINESCENCE SPECTRA FORYb3+-DOPEDCuInS2CRYSTAL

Six crystal field energy levels obtained from the photoluminescence spectra of Yb3+-doped CuInS2semiconductor crystal are calculated from the diagonalization (of energy matrix) method. The root-mean-square (r.m.s) deviation σ is 4.5 cm-1and so the calculated results are in good agreement with the experimental values. The local tetragonal distortion angle θ for the Yb3+center in CuInS2(which is different from the corresponding angle θhin the host crystal) is obtained from the calculation.

Comparative study on the spectroscopic and laser propertiesof mixed vanadates Ybt:Y x Gd1-t-x VO4with different compositions

The room-temperature polarized absorption and emission spectra of Yb doped mixed vanadates Yb0.005:Y0.298Gd0.697VO4, Yb0.007:Y0.407Gd0.586VO4, and Yb0.009:Y0.575Gd0.416VO4 have been studied. The results show that the strongest absorption and emission, occurring at wavelength of 985 nm, correspond to the π polarization, depending on the composition the maximum absorption cross section ranges from 4.8 to 8.5×10-20 cm2, with bandwidths of 9.5—9.9 nm, whereas the maximum stimulated emission cross section varies in the range of 5.8—10.3×10-20 cm2. Continuous-wave laser operation has been realized at room temperature with the mixed crystals through longitudinal pumping with a diode laser. It was found that the laser oscillation behavior differs significantly from one mixed crystal to another:in the case of T=2% (T is the output coupling of the resonator), the coexistence and switching of σ, π polarization states occur on reducing the pump power in the laser oscillation of Yb0.005:Y0.298Gd0.697VO4 and Yb0.009:Y0.575Gd0.416VO4, while the laser oscillation of Yb0.007:Y0.407Gd0.586VO4 is capable of maintaining its π polarization state. In the case of T=5%, however, the laser oscillation generated with Yb0.009:Y0.575Gd0.416VO4 is purely σ-polarized, whereas the laser behavior of Yb0.005:Y0.298Gd0.697VO4 is similar to that exhibited in the case of T=2%.

Magneto-optical spectroscopy and optical detection of EPR spectra of Yb3+ paramagnetic centers with cubic symmetry in single crystals MeF2 (Me = Cd, Ca, Pb)

Cubic paramagnetic centers formed by Yb3+ impurity ions in fluorite-type crystals MeF2 (Me = Cd, Ca, Pb) have been investigated using electron paramagnetic resonance, magnetic circular dichroism, magnetic circular polarization of luminescence, Zeeman splitting of optical absorption and luminescence lines, and optical detection of electron paramagnetic resonance. The g factors of the 2Γ7 state in the excited multiplet 2 F 5/2 of Yb3+ ions in Me F2 crystals, the hyperfine interaction constant 171 A (171Yb) for the excited multiplet 2 F 5/2 in the CaF2 crystal, and the energies and symmetry properties of all energy levels of Yb3+ ions in MeF2 crystals are determined. The crystal-field parameters for the crystals under investigation are calculated.

Growth and spectral properties Yb3+/Na+:CaMoO4 crystal

The Yb3+/Na+:CaMoO4 crystal with dimensions of ø20 × 30 mm3 has been grown by Czochralski method from a flux of Na2MoO4. The absorption and emission spectra of Yb3+/Na+:CaMoO4 crystals were investigated. The absorption bands at 934 nm have a FWHM of 59 nm for π polarisation and 65 nm for σ polarisation respectively. The absorption cross-sections σa are 1˙73 × 10–20 cm2 for π polarisation and 1˙44 × 10–20 cm2 for σ polarisation at 934 nm respectively. The emission bands have a FWHM of 68 nm at 1022 nm for π polarisation and 65 nm at 1023 nm for σ polarisation respectively. The emission cross-sections σe are 1˙14 × 10–20 cm2 at 1022 nm for π polarisation and 1˙27 × 10–20 cm2 at 1023 nm for σ polarisation respectively. The Yb3+/Na+:CaMoO4 crystal may be considered as a potential laser gain material.

Continuous-wave and Q-switched microchip laser performance of Yb:Y_3Sc_2Al_3O_12 crystals

Optical properties of Yb:Y(3)Sc(2)Al(3)O(12) crystal were investigated and compared with those from Yb:YAG crystals. The broad absorption and emission spectra of Yb:Y(3)Sc(2)Al(3)O(12) show that this crystal is very suitable for laser-diode pumping and ultrafast laser pulse generation. Laser-diode pumped continuous-wave and passively Q-switched Yb:Y(3)Sc(2)Al(3)O(12) lasers with Cr(4+):YAG crystals as saturable absorber have been demonstrated for the first time. Continuous-wave output power of 1.12 W around 1032 nm (multi-longitudinal modes) was measured with an optical-to-optical efficiency of 30%. Laser pulses with pulse energy of over 31 microJ and pulse width of 2.5 ns were measured at repetition rate of over 12.7 kHz; a corresponding peak power of over 12 kW was obtained. The longitudinal mode selection by a thin plate of Cr(4+):YAG as an intracavity etalon was also observed in passively Q-switched Yb:Y(3)Sc(2)Al(2)O(12) microchip lasers.

Effect of ytterbium concentration on cw Yb:YAG microchip laser performance at ambient temperature – Part I: Experiments

The microchip laser performance of Yb:YAG crystals doped with different ytterbium concentrations (CYb=10, 15, and 20 at. %) has been investigated at ambient temperature without active cooling of the gain media. Efficient laser oscillation for a 1-mm-thick YAG doped with 10 at. % Yb3+ ions was achieved at 1030 and 1049 nm with slope efficiencies of 85% and 81%, correspondingly. The laser performance of heavy-doped Yb:YAG crystals was limited by the thermal population at terminated lasing level and thermal lens effect at room temperature without sufficient cooling of the samples. The laser emitting spectra of Yb:YAG microchip lasers with different Yb concentrations and output couplings are addressed with the local temperature rise, due to the absorption of the pump power inside the gain media under different pump levels.

Growth and spectral properties of Yb,Tm:YAG crystal

The YAG crystal codoped with Yb3+ and Tm3+ has been grown by Czochralski (Cz) method. The crystal structure of the crystal has been determined by X-ray diffraction analysis. The absorption and emission spectra of Yb,Tm:YAG crystal at room temperature have also been studied. The emission cross-sections have been calculated by Fuechtbauer-Ladenburg formula and reciprocity method. (C) 2007 Elsevier B.V. All rights reserved.

Spectra analysis of Yb: Y3Al5O12 crystals with different Yb doping concentration

Yb：Y3Al5O12(Yb:YAG) single crystals with Yb3+ doping level of 5.4at%, 16.3at%, 27.1at%, 53.6at%, and 100at% were grown by the Czochralski method. The effects of different Yb3+ doping level on the absorption spectra and fluorescence spectra were studied. The results showed that the real absorption coefficient of the absorption peaks increases linearly with the increasing of Yb3+ doping level in Yb:YAG crystals. Absorption band oscillator strengths of Yb：YAG crystals were calculated with Smakula formula and the effects of different Yb3+ doping level on the oscillator strengths were also studied. The concentration quenching of fluorescence was observed when the Yb3+ doping level reached 27.1at% in Yb:YAG crystals. The shape of fluorescence spectra of Yb:YAG could be significantly influenced when the Yb3+ doping level is higher than 53.6at%.

EPR of rare-earth ion clusters in mixed crystals Ba1−x La x F2+x doped with Yb3+ Ion

Electron paramagnetic resonance (EPR) spectra of Yb3+ ions in the mixed crystals (BaF2)1−x X(LaF3) x withx≈0.01 have been investigated by the electron spin echo method at a frequency of 94.9 GHz and compared with the spectra obtained by the continuous-wave EPR at a frequency of 9.5 GHz. Some spectral lines were identified within the framework of the simple cluster model proposed in our previous work (L. K. Aminov, R. Yu. Abdulsabirov, M. R. Gafurov, S. L. Korableva, I. N. Kurkin, S. P. Kurzin, R. M. Rakhmatullin, A. G. Ziganshin: Appl. Magn. Reson. 28, 41–53, 2005). Clusters consist of trigonal dipoles La−F and Yb−F (a rare-earth ion with a charge compensator) and are formed beginning with small concentrationsx≈0.001. The lines identified in the present work were attributed to the clusters with configurations Yb−F−La−F and La−F−Yb−F−La−F.

Optical study of Yb3+/Yb2+ conversion in CaF2 crystals

Yb3+ ions with various site symmetries have been observed in the absorption and emission spectra ofYb3+:CaF2 crystals,both γ-irradiated and annealed in hydrogen. The absorption intensity value is found to be much higher forthe γ-irradiated crystal and strongly dependent on the gamma dose. The UV absorption spectra ofγ-irradiatedand H2-annealedCaF2:5 at.%Yb3+ crystals arequite similar. Yb2+ absorption bands are observed at 360, 315, 271, 260, 227 and 214 nm,which are called A, B, C, D, F and G bands, respectively. Forγ-irradiatedCaF2:30at.% Yb3+, an additional band at 234 nm can be seen. It is suggested that only a negligible amount ofYb3+ ions are convertedinto Yb2+ under theγ-irradiation.The presence of Yb2+ is confirmed by the 565 and 540 nm luminescence under 357 nm excitation. Itis also suggested that the excitation in the A, C, D and F absorption bands ofYb2+ gives rise tophoto-ionization of Yb2+ ions and electrons in the conduction band to form the excitedYb3+ ions whichemit IR Yb3+ luminescence.The UV absorption and emission spectra obtained forγ-irradiatedand H2-annealedcrystals have different structures. This suggests that different mechanisms are responsible for the creationof Yb2+ ions.γ-irradiation favoursYb2+ isolated centresby reduction of Yb3+ ions located at Ca2+ lattice sites, whereas annealing in hydrogen favoursYb2+ centresneighbouring Yb3+ ions when a Yb3+ ion pair captures a Compton electron. Also,γ-irradiation does notchange the position of Yb3+ ions converted into Yb2+ in the CaF2 lattice.In the case of H2 annealing, a Yb3+ ion converted to Yb2+ is shifted to the Ca2+ position in the lattice.

Growth and Spectroscopic Study of Yb3+-Activated YVO4Crystals

The absorption and luminescence spectra of Yb3+ and the luminescence decay kinetics for the Yb3+2F5/2 level in YVO4:Yb3+ crystals are studied. The luminescence cross section for the Yb3+2F5/2 → 2F7/2transition in YVO4:Yb3+ is determined by the Fuchtbauer–Ladenburg method, and the radiative lifetime of Yb3+ is evaluated.

A pulsed EPR study of clustering of Yb 3+ ions incorporated in GeO 2 glass

The structural aspects of clustering of Yb 3+ ions and the paramagnetic behavior of these clusters have been investigated in GeO 2 glasses doped with 140–1100 ppm by weight of Yb 2O 3 using time-domain electron paramagnetic resonance (EPR) spectroscopic techniques. The echo-detected EPR (EDEPR) spectra of Yb 3+ ions and their unusual dependencies on microwave power and magnetic field have been found to be indicative of the formation of clusters of these rare earth ions in GeO 2 glass that behave as non-Kramers type spin systems. The magnetic field and concentration dependence of phase relaxation rates of Yb 3+ in these glasses further substantiate such a scenario and indicate the formation of clusters of Yb 3+ ions. A comparison of the EDEPR spectra with calculated cw-EPR line shapes yields a semi-quantitative measure of the typical cluster size of ⩾3 Yb atoms and intra-cluster Yb–Yb distances of 3.5–4.0 Å in these glasses at doping levels of ⩾350 ppm of Yb 2O 3.