Upconversion Emission in Er^(3+) Doped Novel Bismuthate Glass

Novel Er3+-doped bismuth lead strontiam glass was fabricated and characterized, and the absorption spectrum and upconversion spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ωt (t=2, 4, 6) were found to be Ω2=3.27×10-20 cm2, Ω4=1.15×10-20 cm2, and Ω6=0.38×10-20 cm2. The oscillator strength, the spontaneous transition probabilities, the fluorescence branching ratios, and excited state lifetimes were also measured and calculated. The upconversion emission intensity varies with the power of infrared excitation intensity. A plot of log Iup vs log IIR yields a straight line with slope 1.86, 1.88 and 1.85, corresponding to 525, 546, and 657 nm emission bands, respectively, which indicates that a two-photon process for the red and green emission.

Large phase shift of spatial soliton in lead glass by cross-phase modulation in pump-signal geometry

We investigate the co-propagation of a strong pump beam and a weak signal beam in lead glass, and find that the large phase shift of the strongly nonlocal spatial optical soliton （SNSOS） can be realized via cross-phase modulation. The theoretical study suggests a synchronous propagation of the pump SNSOS and the signal SNSOS under the required initial condition. A π-phase shift of the signal SNSOS is experimentally obtained by changing the power of the pump SNSOS by about 13 mW around the soliton critical power, which agrees qualitatively with our theoretical prediction. The ratio of the phase shift rate of the signal SNSOS to that of the pump SNSOS shows a close match to the reciprocal of the ratio between their wavelengths.

Dependence of the emission electric dipole line strength of Eu^(3+) on the composition of lead borate glasses

Lead borate glasses xB2O3+(99–x)PbO+0.5Eu2O3(x=70,60,...,10) were prepared by melt-quenching method.The luminescent properties were characterized with excitation and emission spectra.The emission intensities for 5D0-7FJ(J=0–4) were analyzed to give variation of the relative electric dipole line strengths with the composition of glasses so as to examine the crucial implicit assumption of independent electric dipole line strength on the composition of glass in the Phys.Rev.Lett.2003,91,203903 paper studying l...

FORMATION AND CRYSTALLIZATION OF LEAD HALIDE BASED GLASSES

A series of new glass compositions based on PbX2 (X: Cl, Br or I) have been studied. Binary and ternary glasses resulted from the association of PbI2, Pb-Cl-2, AgI, KCl and KBr. By means of differential scanning calorimetry (DSC), the mechanism and kinetics of crystallization process were studied. X-ray diffraction studies demonstrate that there is the formation of complicated crystalline phases in crystallized lead iodide based glasses. By heat treating halide glasses of appropriate composition under adequate heating temperature and duration, the lead iodide based glasses could be converted into glass-ceramics with microcrystal size less 1 mu m of which mechanical properties are improved.

Enhanced 1.8 μm emission in Er^(3+)/Tm^(3+) co-doped lead silicate glasses under different excitations for near infrared laser

A detailed study of the fluorescence emission properties and energy transfer mechanism in Er^（3＋）/Tm^（3＋） co-doped lead silicate glasses was reported. Enhanced near infrared 1.8 μm and visible up-conversion emissions were investigated under 808 and 980 nm excitations, respectively. The energy transfer mechanism between Er^（3＋） and Tm^（3＋） was analyzed according to the absorption spectra, the emission spectra and the level structures of Er^（3＋） and Tm^（3＋）. The energy transfer efficiency between Er^（3＋） and Tm^（3＋） reached 68.1% in the Er^（3＋）/Tm^（3＋） co-doped lead silicate glasses when pumped by 808 nm laser diode. Based on the absorption spectra, the Judd-Ofelt parameters, spontaneous emission probability, absorption and emission cross sections, gain coefficients were calculated and analyzed. It was found that the calculated emission cross section and the maximum gain coefficient around 1.8 μm were 4.9×10^（–21）cm^2 and 1.12 cm^（–1）, respectively. These results indicated that the Er^（3＋）/Tm^（3＋） co-doped lead-silicate glasses had potential application in near infrared lasers.

Local structure and luminescent properties of lead phosphate glasses containing rare earth ions

Local structure and luminescent properties of lead phosphate glasses containing rare earth ions were studied. Optically active ions such as Eu^3＋, Dy^3＋, Tb^3＋ and Er^3＋ were chosen as dopants. The local structure was verified using X-ray diffraction and Fourier transform inflared （FT-IR） spectroscopy. The visible luminescence bands recorded for the studied samples corresponded to ^5D0→^7Fj （J=0÷4） transitions of Eu^3＋, ^4F9/2→^6Hj/2 （J=11÷15） transitions of Dy^3＋, ^5D3→^7FJ, （J＇=1÷6） and ^5Da→^7FJ （J=3÷6） transitions of Tb^3＋, and ^4S1/2→^4I15/2 transitions of Er^3＋.

Energy transfer from Tb^(3+) to Eu^(3+) in zinc lead borate glass

In order to sensitize the luminescence of Eu3+ ions in heavy metal glass,zinc lead borate glass samples containing various concentrations of Eu3+ and Tb3+ ions were prepared to study the Tb3+ to Eu3+ non-radiative energy transfer phenomena.Energy level structures of Tb3+ and Eu3+ ions were plotted to show the excitation and energy transfer routes.Efficient energy transfer from Tb3+ to Eu3+ was observed and studied qualitatively in terms of doping concentrations.The sensitization turned out to be less effective than expected.Further studies to characterize the oxidation of Tb3+ into tetravalent state and to examine the mechanism of energy transfer are proposed.