Growth and Spectroscopic Characteristics of Yb3＋：LiGd（WO4）2 Crystal

The Yb3+:LiGd(WO4)2 crystal with the dimension of Φ15×35 mm3 was grown by Czochralski technique. The spectroscopic characterization and fluorescence dynamics of Yb3+ in Yb3+:LiGd(WO4)2 crystal were investigated. The Yb3+:LiGd(WO4)2 crystal exhibits a broad absorption band centered near 975 nm with the linewidths of 16 and 11 nm and maximal absorption cross-section of 3.60 × 10-20 and 2.90 × 10-20 cm2 for π- and σ-polarization, respectively. The emission broadband has an FWHM of 47 and 45 nm with the emission cross sections of 3.92 × 10-20 and 3.34 × 10-20 cm2 at 1020 nm for π- and σ-polarization, respectively. The measured fluorescence lifetime is 398 μs. The blue light emission around 480 nm through cooperative upconversion from the de-excitation of excited Yb3+-Yb3+ pairs at 4 K was observed under 932-nm excitation and demonstrated.     

Growth and Spectral Characterization of Nd3+∶(Sr0.7Ca0.3)3Y(BO3)3 Crystal

A Nd3+ :(Sr0.7Ca0.3)3Y(BO3)3 crystal with dimensions of 17×23 mm3 has been grown by the Czochralski method. The spectroscopic characterization of Nd3+ :(Sr0.7Ca0.3)3Y(BO3)3 crystal was investigated. The polarized absorption cross-sections of Nd3+ :(Sr0.7Ca0.3)3Y(BO3)3 crystal are 2.81×10-20 cm2 with full width at half maximum (FWHM) of 14 nm at 808 nm for σ-polarization and 2.04×10 -20 cm 2 with FWHM of 19 nm at 807 nm for σ-polarization, respectively. The polarized emission cross-sections of Nd3+ :(Sr0.7Ca0.3)3Y(BO3)3 crystal are 12.2×10-20 cm2 at 1062 nm for the π-polarization and 13.6×10-20 cm2 at 1061 nm for the σ-polarization, respectively. After the Ca 2+ ion partly substitutes for Sr2+ ion in the Sr3Y(BO3)3 crystal to form the (Sr0.7Ca0.3)3Y(BO3)3 solid solution, it can improve the quantum efficiency of Nd3+ :(Sr0.7Ca0.3)3Y(BO3)3 crystal. The quantum efficiency is 31.7%. These results may be regarded Nd3+ :(Sr0.7Ca0.3)3Y(BO3)3 crystal as a potential solid-state laser material.     

Growth and Spectral Characteristics of Yb3＋-doped LiGd（MoO4）2 Crystal

The Yb3+-doped LiGd(MoO4)2 crystal with the size up to Φ20×30 mm3 has been grown by Czochralski technique.The polarized room temperature absorption and emission spectra have been investigated.This crystal exhibits a broad absorption band centered at 975 nm with an FWHM of 43 and 59 nm for π-and σ-polarization,respectively,and the corresponding maximal absorption cross-sections are 3.36 and 2.42×10-20 cm2.The emission broadband has an FWHM of 47 and 54 nm for π-and σ-polarization,respectively,with the corresponding emission cross sections of 3.92 and 3.34 × 10-20 cm2 at 1020 nm.The measured fluorescence lifetime is 287 μs.     

Structure of High Temperature Phase α-Ba3Y（BO3）3 Crystal

1 INTRODUCTION To the present, the series of compounds M3Ln- (BO3)3 (M = Sr, Ba and Ln = La-Lu, Sc, Y) with space group P63cm or 3R have been reported[1～5]. Some of them exhibit interesting optical properties when doped into the active Cr3+ or Yb3+ ions as laser materials. For example, the Yb3+-doped Sr3Y- (BO3)3 crystal is a promising laser material for both tunable and femtosecond laser applications[6～8]. The Ba3Y(BO3)3 crystal melts congruently at 1256 ℃ and has a phase…     

Structure of Low Temperature Phase b-Ba_3Y(BO_3)_3 Crystal

1 INTRODUCTION Recently the series of compounds M3Ln(BO3)3 (M = Sr, Ba and Ln = LaLu, Sc, Y) with space group P63cm or -3R have been reported[1～5], and some of them exhibit interesting optical properties when doped with the active Cr3+ or Yb3+ ions as laser materials. For example, Yb3+-doped Sr3Y- (BO3)3 crystal is a promising laser material for both tunable and femtosecond laser applications[6～8]. The Ba3Y(BO3)3 crystal melts congruently at 1256 ℃ and has a phase transitio…     

Growth,Structure,and Spectroscopic Characteristics of the Nd^3＋：LiGd（WO4）2 Crystal

The Nd3+:LiGd(WO4) 2 crystal with dimensions of 25mm×28mm×16mm was grown by the top-seeded solution growth method from the 60 mol% Li2W2O7 flux. LiGd(WO4) 2 crystallizes in the tetragonal system with space group I41/a(C4h6) and cell parameters: a = 5.1986 and c = 11.2652 . The hardness is about 5.0 Mohs' scale. The specific heat is 0.40 J·g-1·K-1 at 50 oC. The thermal expansion coefficients for a-and c-axes are 1.314×10-5 and 2.052×10-5 K-1,respectively. The room-temperature polarized absorption and emission spectra and the fluorescence decay curve was measured. The parameters of oscillator strengths,the spontaneous transition probabilities,the fluorescence branching ratios,the radiative lifetimes,and the emission cross sections have been investigated based on Judd-Ofelt theory and Füchtbauer-Ladenburg method. The absorption cross-section is 5.19×10-20 cm2 at 805 nm for π-polarization and its line width is 15 nm;the emission cross section is 1.726×10-19 cm2 at 1060.5 nm for π-polarization. The fluorescence and radiative lifetimes are 86 and 158 μs,respectively. The fluorescence quantum efficiency is 54.43%.     

Growth and Characterization of Crystal Nd_(0.06)Y_(0.94)Sr_6Sc(BO_3)_6

<正>The crystal of Nd0.06Y0.94Sr6Sc(BO3)6 with the dimensions up to 35 mm × 28 mm × 13 mm was grown by a top-seeded solution growth method from Li6B4O9 flux. The grown crystal was characterized by X-ray powder diffraction. The optical absorption of the crystal shows that it has a strong absorption band at 8070 A, and the absorption coefficient is 2.17cm-1 with a FWHM of 41 A, which can match with the wavelength of the diode-laser (LD) and is suitable for the LD pumping. Based on the Judd-Ofelt theory, the three parameters of line oscillator strength Ω(λ) (λ = 2, 4 and 6) of the Nd3+ion in the crystal were calculated as follows: Ω2= 1.194 × 10-20, Ω4= 4.186 × 10-20 and Ω6 = 3.351 × 10-20cm2, which are relatively larger. The results indicate that the crystal Nd0.06Y0.94Sr6Sc(BO3)6 may be a kind of high-efficient laser material for diode-pumped.     

Spectral properties of Nd-doped BiB_3O_6 crystal

Transparent Nd : BiB3O6 crystal has been grown by top-seeded method. The refraction indices of the crystal were measured and the parameters of chromatic dispersion were fitted. The room temperature absorption spectra of the crystal have been measured and compared with that of 0.2 mol/L NdCI3 solution. According to Judd-Ofelt (JO) theory, the spectral strength parameters Ω2 = 0.1776×10-20 cm2, Ω4 = 0.1282×10-20 cm2 and Ω6 = 0.1357×10-20 cm2 of Nd3+ ion were fitted. The radiative transition probabilities AJ,(?), oscillator strengths fJ,(?), radiative lifetime T and the branching ratio β(?) have all been calculated. Based on these parameters, the properties and application perspective are discussed.     

ABSORPTION SPECTRA OF 4f ELECTRON TRANSITIONS IN THE SYSTEM OF NEODYMIUMSEMIXYLENOL ORANGE-CETYLPYRIDINIUM CHLORIDE

In this paper the absorption spectra of Nd-SXO-CPC complex by 4f electron transitions have been studied by zero-order and fourth-order derivative spectrophotome-try. The molar absorptivity is 2.6×10~3 1.mol~(-1).cm~(-1) at 585 nm, the fourth-order derivative molar absorptivity is 1.4×10~4 1.mol~(-1).cm~(-1) at 584.5(-) and 587(+) nm. They are 300 times and 1600 times greater than those of the chloride, respectively.     

Synthesis and Structure of Ba3La2（BO3）4 Crystal

1 INTRODUCTION At present the researches on more efficient solid-state laser materials become more important for the rapid development of diode-laser pumped solid-state laser. More researches have been devoted to the double borate compounds RX3(BO3)4 (R = Y, La, Gd and X = Y, Al, Sc), some of which exhibit good chemical and physical properties[1～10]. The rare earth and alkali-halide double borates M3Ln2(BO3)4 (M = Ca, Sr, Ba and Ln = LaLu and Y) were reported in literatures[11…     

Growth and Spectroscopic Properties of Nd3＋：Sr3Gd2（BO3）4 Crystal

<正>This paper reports the growth,X-ray diffraction and spectroscopy of Nd~(3+):Sr_3Gd_2(BO_3)_4 crystal.A Nd~(3+):Sr_3Gd_2(BO_3)_4 crystal with dimensions ofφ20×45 mm~3 has been grown by the Czochralski method.Nd~(3+):Sr_3Gd_2(BO_3)_4 crystal belongs to the orthorhombic system,space group Pnma(D_(2h))with a=0.7401,b=1.604 and c=0.8755 nm.The absorption and emission spectra of Nd~(3+):Sr_3Gd_2(BO_3)_4 were investigated.The absorption cross sectionσ_a is 3.11×10~(-20)cm~2 at 808 nm. The absorption transition at 808 nm has an FWHM of 14 nm.The luminescence lifetimeτ_f is 51.7 us.The emission cross sectionσ_e at 1064 nm wavelength is 1.09×10~(-19)cm~2.     

Growth and Optical Properties of Sr_6YbSc(BO_3)_6 Crystal

1INTRODUCTION As is well known,the Yb3 ion has some advan-tages in comparison with Nd3 as laser active ion,for it has only two manifolds,i.e.,the ground2F7/2state and the excited2F5/2state.There is no excited state absorption reducing effective laser cross-section,no concentration quenching,no up-conversion,and three or four times longer emission lifetime than Nd3 ion.Yb3 ion exhibits a strong and broad ab-sorption band at ca.970nm and can be easily pumped with InGaAs diode lasers.The …     

Host sensitization of Tb3+ ions in tribarium lanthanide borates Ba3Ln (BO3)3 (Ln = Lu and Gd)

The vacuum-ultraviolet (VUV) spectroscopic properties of undoped and Tb(3+)-doped borates Ba(3)Ln(BO(3))(3) (Ln = Lu and Gd) with different crystal structures were investigated by using synchrotron radiation. Ba(3)Lu(BO(3))(3) (BLB) crystallizes in a hexagonal structure, whereas Ba(3)Gd(BO(3))(3) (BGB) crystallizes in a trigonal structure. The maximum host absorption for BLB and BGB was found to locate at ~179 and ~195 nm, respectively. Upon host excitation, BLB exhibits an intrinsic broad UV emission centered at 339 nm, which is attributed to the recombination of self-trapped excitons that may presumably be associated with band-gap excitations or molecular transitions within the BO(3)(3-) group. In contrast to BLB, no broad emission but line emission ascribed to a Gd(3+)(6)P(J)-(8)S(7/2) transition was observed in the emission spectrum of BGB. Upon doping of Tb(3+) ions into the hosts of BLB and BGB, an efficient energy transfer from the host excitations to Tb(3+) via host/Gd(3+) emission was observed, showing that host sensitization of Tb(3+) occurs in these rare-earth borates.     

Yb3+敏化宽波带掺Er3+氟磷酸盐玻璃的发光性质及Judd-Ofelt理论研究

采用高温熔融法制备了一种新的Er3+/Yb3+共掺氟磷酸盐玻璃,测试和分析了其密度、吸收光谱以及荧光光谱,讨论了Er3+离子和Yb3+离子对光谱性质的影响.根据Judd-Ofelt理论计算了玻璃中Er3+离子的强度参数Ωt(t=2,4,6),分别为Ω2=4.36×10-20cm2,Ω4=1.35×10-20cm2,Ω6=0.79×10-20cm2,以及Er3+离子4I13/2能级荧光寿命τm=8.26ms.主发射峰1.53μm处半高宽(FWHM)为68nm.根据McCumber理论计算了Er3+的受激发射截面σe=8.5×10-21cm2.比较了不同玻璃基质中Er3+离子的光谱特性,结果表明:Er3+/Yb3+双掺氟磷酸盐玻璃在1.53μm附近具有较宽的半高宽和较大的受激发射截面,是一种高增益掺铒光纤放大器的理想介质材料.     

Synthesis, structure, and thermally stable luminescence of Eu(2+)-doped Ba2Ln(BO3)2Cl (Ln = Y, Gd and Lu) host compounds

A new family of chloroborate compounds, which was investigated from the viewpoint of rare earth ion activated phosphor materials, have been synthesized by a conventional high temperature solid-state reaction. The crystal structure and thermally stable luminescence of chloroborate phosphors Ba(2)Ln(BO(3))(2)Cl:Eu(2+) (Ln = Y, Gd, and Lu) have been reported in this paper. X-ray diffraction studies verify the successful isomorphic substitution for Ln(3+) sites in Ba(2)Ln(BO(3))(2)Cl by other smaller trivalent rare earth ions, such as Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb. The detailed structure information for Ba(2)Ln(BO(3))(2)Cl (Ln = Y, Gd, and Lu) by Rietveld analysis reveals that they all crystallize in a monoclinic P2(1)/m space group. These compounds display interesting and tunable photoluminescence (PL) properties after Eu(2+)-doping. Ba(2)Ln(BO(3))(2)Cl:Eu(2+) phosphors exhibit bluish-green/greenish-yellow light with peak wavelengths at 526, 548, and 511 nm under 365 UV light excitation for Ba(2)Y(BO(3))(2)Cl:Eu(2+), Ba(2)Gd(BO(3))(2)Cl:Eu(2+), and Ba(2)Lu(BO(3))(2)Cl:Eu(2+), respectively. Furthermore, they possess a high thermal quenching temperature. With the increase of temperature, the emission bands show blue shifts with broadening bandwidths and slightly decreasing emission intensities. It is expected that this series of chloroborate phosphors can be used in white-light UV-LEDs as a good wavelength-conversion phosphor.     

Green and red light emission by upconversion from the near-IR in Yb(3+) doped CsMnBr3

Direct near-IR excitation of Yb(3+) 2F(7/2)-->(2)F(5/2) levels at 10126, 10138, and 10596 cm(-1) in CsMnBr3:0.5%Yb(3+) leads to three types of luminescence at cryogenic temperatures: near-IR Yb(3+) emission and green and red upconverted luminescence. The green luminescence around 20 000 cm(-1) is identified as cooperative Yb(3+) pair upconversion. The broad red upconversion luminescence band centered at 14 700 cm(-1) is ascribed to the 4T(1g)-->6A(1g) transition of Mn(2+). Pulsed measurements indicate a sequence of ground-state absorption and excited-state absorption steps for the red upconversion process. One- and two-color excitation experiments support this, and we conclude that the red upconversion occurs by an exchange mechanism involving Yb(3+) and Mn(2+). The Yb(3+) 2F(5/2)-->(2)F(7/2) near-IR emission around 10 000 cm(-1) is also observed after Mn(2+) excitation at 21 838 cm(-1). This is indicative of a Mn(2+) 4T(1g)--> Yb(3+) 2F(5/2) relaxation process, which is a potential loss process for upconversion efficiency.     

Fluorescence investigation of Ho3+ in Yb3+ sensitized mixed-alkali bismuth gallate glasses

Efficient 2.0 microm infrared and visible upconversion emissions have been observed in Ho3+/Yb3+ co-doped mixed-alkali bismuth gallate (LKBBG) glasses having a maximum-phonon energy of 673 cm(-1). The Judd-Ofelt parameters Omega2, Omega4 and Omega6 of Ho3+ indicate that there is a high asymmetry and strong covalent environment in LKBBG glasses. The large absorption and emission cross-sections of Yb3+ confirm that it is a suitable sensitizer for capturing and transferring pump energy to Ho3+. The emission cross-section profile for the 5I7-->5I8 transition is derived using the reciprocity method and the peak value is 5.54 x 10(-21)cm2, which is much larger than the value in fluorozircoaluminate glasses. LKBBG glasses exhibit low maximum-phonon energy and large refractive index, and it is possible to achieve an effective 1.66 microm U-band emission of Ho3+ under 900 nm laser radiation.