Search

Sm3+ doped yttria transparent ceramics (Sm x Y 1-x) 2 O 3 (x = 0.01, 0.015, 0.03) were fabricated by Spark Plasma Sintering method. Absorption spectra, as well as emission spectra and luminescence lifetime were carried out at room temperature. Judd-Ofelt (J-O) theory was used to calculate the Ω t (t = 2, 4, 6) intensity parameters. The spontaneous transition probabilities, radiative lifetime, branching ratio, and stimulated emission cross-sections have been calculated for 4G 5/2 excited level. The emission cross section for the 4G 5/2 → 6H 7/2 transition at about 607 nm was calculated to be 6.73 × 10−22 cm2. The results indicate that Sm:Y 2 O 3 ceramic may be a potential reddish orange-light laser material around 607 nm. [ABSTRACT FROM AUTHOR]

The luminescence properties of 0.5%Pr-doped BGO crystals grown by using the micro-pulling down technique were carefully investigated. Room temperature absorption spectra were registered and analyzed within the framework of the Judd-Ofelt formalism and the best fit to the data is obtained by using a modified treatment allowing for the admixture of intensity enabling wave-functions. The results indicate 3P 0 and 1D 2 radiative lifetimes of about 5.7 μs and 79 μs, in perfect agreement with the time-constants derived from the measured fluorescence decays at room and liquid-nitrogen temperatures. Registration of time-resolved emission and excitation spectra and calibration of the 3P 0 emission spectrum in cross section unit clearly indicate that Pr-doped BGO could be the first isotropic crystalline material leading to efficient diode-pumped laser operation at room temperature with laser performances, at least in the deep-red spectral region, comparable to that found with the most important anisotropic Pr-doped fluoride and oxide crystals. • Pr:Bi 4 Ge 3 O 12 crystal fibers are successfully grown by micro-pulling down. • Absorption spectra are analyzed by using the Judd-Ofelt formalism. • Emission, excitation spectra are registered from the near-UV to the deep-Red. • It is found a 3P0 emission lifetime of 5.7 μs for a quantum yield close to 1. • Record emission cross-sections are obtained in the red and deep-red. [ABSTRACT FROM AUTHOR]

Yb,Pr:CaF 2 crystals have been grown successfully by the temperature gradient technique(TGT). The absorption spectra, fluorescence spectra, fluorescence decay lifetime of Pr3+ ions in CaF 2 crystal sensitized by different Yb3+ ions concentration have been measured. The effective J-O intensity parameters were fitted to be Ω 2 =0.36 × 10−20cm2, Ω 4 =2.89 × 10−20cm2, Ω 6 =6.69 × 10−20cm2 for 0.3 at.%Pr,1.5 at.%Yb:CaF 2. And the emission cross sections of 3P 1 →3H 5 (535 nm), and 3P 0 →3F 4 (750 nm) are calculated to be 2.02 × 10−20cm2, and 2.50 × 10−20cm2 with the FWHM of 17.2 nm, and 10.5 nm, respectively. The fluorescence lifetime of 3P 0 has achieved great increasing by sensitizing of Yb3+ ion. Not only the up-conversion luminescence can be achieved, but also the broad band emission from 1D 2 energy level can be observed. The results show that Yb,Pr:CaF 2 could be a potential laser gain medium for visible and near-IR laser operation. • Not only the up-conversion luminescence can be achieved, but also the broad band emission from 1D 2 energy level can be observed by Yb3+ ion sensitizing. • Spectral properties and Judd-Ofelt parameters of Yb,Pr:CaF 2 crystal were investigated and analysed. [ABSTRACT FROM AUTHOR]

We report on the comparative growth and spectroscopy of Eu3+-doped Y 3 Al 5 O 12 (YAG) and Y 3 ScAl 4 O 12 crystals grown by the micro-pulling-down (μ-PD) method. The structure of the as-grown crystals was determined by X-ray diffraction (XRD) and Raman spectroscopy. The absorption spectra of the crystals are dominated by a strong line centered at 395 nm, matching well with the emission of commercial ultraviolet laser diodes. The Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals exhibit strongest red emission centered at 710 nm and the full width at half maximum (FWHM) was calculated to be 2.03 and 3.19 nm, respectively. The fluorescence decay curves of 5D 0 levels were measured and discussed. All the results indicate that the Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals are promising candidates for red luminescent/laser materials. • Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals were successfully grown by the micro-pulling-down technique for the first time. • The structure parameters of Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals were investigated by XRD. • Spectral parameters of Eu:YAG and Eu:Y 3 ScAl 4 O 12 crystals were obtained and compared. [ABSTRACT FROM AUTHOR]