Up-conversion processes of rare earth ions in heavy metal glasses

Heavy metal lead germanate glasses doubly doped with Yb^3＋ and Ln^3＋ ions （Ln=Er, Tin） were investigated. Up-conversion spectra of Er^3＋ and Tm^3＋ were registered under diode-laser excitation of Yb^3＋. Up-conversion luminescence bands corresponded to ^4S3/2→^4I15/2 （green） and ^4F9/2→^4I15/2 （red） transitions of Er^3＋ as well as ^1G4→^3H6 （blue） and ^3Ha→^3H6 （N]R） transitions of Tm^3＋, respectively.

Energy transfer processes from Yb^(3+) to Ln^(3+) (Ln=Er or Tm) in heavy metal glasses

Heavy metal glasses doubly doped with Yb3＋ and Ln3＋ ions （Ln=Er or Tm） were studied. Glass host matrices were limited to lead borate glass and lead germanate glass. Efficient resonant （yb3＋-Er3＋） and non-resonant （yb3＋-Tm3＋） energy transfer was ob- served for the studied systems. Near-infrared luminescence spectra at 1.53 μm （Er3＋） and 1.9 gm （Tm3＋） were detected under excita- tion of Yb3＋ by 975 nm diode laser line. They corresponded to 4I13/2→4115/2 （Er3＋） and 3F4→3H6 （Tm3＋） transitions of rare earth ions, respectively. The unusual large spectral linewidth nearly close to 110 nm for 4I13/2→4I15/2 transition of Er3＋ ions in lead borate glass was obtained, whereas long-lived near-infrared luminescence at 1.53 gm was detected in lead germanate glass. Quite different situa- tion was observed for yb3＋-Tm3＋ doubly doped glasses. In contrast to lead borate glass, near-infrared （3F4→3H6） luminescence spectra were registered for Tm3＋ ions in lead germanate glasses, only. These phenomena strongly depended on stretching vibrations of glass host, which was confirmed by FT-IR spectroscopy.

Broadband 1.53 μm emission in Er^(3+)-doped Ga-Bi-Pb-Ge heavy metal oxide glasses

We investigated the thermal stability and spectroscopic properties of the 1.53 μm emission from ^4I13/2→^4I15/2 transition of Er^3＋ ions in Er^3＋/Yb^3＋-codoped Ga-Bi-Pb-Ge heavy metal oxide glass for use in broadband fiber amplifiers. It was noted that the addition of GeO2 effectively enhanced the thermal stability of the heavy metal oxide glass studied. The emission peak located at approximately 1530 nm with a full width at haft-maximum of approximately 58 nm. The measured lifetime and the calculated emission cross-section of this transition were -3.2 ms and -10.3×10^-21 cm^2, respectively. As a result, Ga-Bi-Pb-Ge heavy metal oxide glasses were assumed to be potential host material for the 1.53 μm broadband optical fiber amplifiers.

Relationship between Composition, Density and Refractive Index for Heavy Metal Fluoride Glasses

The density and the refractive index for various compositions of heavy metal fluoride (HMF) glasses, used to make low loss optical wave guides, have been measured by standard archimedes method and by using as Pulfrich refractometer respectively. The density as a function of composition is calculated considering the effective volume of the ions contained in the glass to be invariant. The refractive index as a function of composition is also calculated, based on the Lorenz Lorentz equation, by computing the electronic polarizability of HMF glasses. All calculated results are in good agreement with the observed data.

Spectroscopic Properties and Judd-Ofelt Theory Analysis of Er^(3+)-Doped Heavy Metal Oxyfluoride Silicate Glass

Er^(3+)-doped heavy metal oxyfluoride silicate glass was fabricated and characterized, and the absorption spectrum and fluorescence spectrum of the glass were studied. The Judd-Ofelt intensity parameters Ω_t (t =2, 4, 6), spontaneous transition probability, fluorescence branching ratio and radiative lifetime of each energy levels for Er^(3+) were calculated by Judd-Ofelt theory, and stimulated emission cross-section of (()~4I_(13/2))→(()~4I_(15/2)) transition was calculated by McCumber theory. The results show that fluorescence full width at half maximum and stimulated emission cross-section of Er^(3+)-doped heavy metal oxyfluoride silicate glass are broad and large, respectively. Compared with other host glasses, the gain bandwidth property of Er^(3+)-doped heavy metal oxyfluoride silicate glass is close to those of tellurite and bismuth glasses, and has advantage over those of silicate, phosphate and germante glasses.

S tudy on Doped Fluoride Glasses for Scintillation Applications

This paper studies the properties of fluoride glasses for use in particle calorimeters or in optical fibers. The effects of major and minor impurities in manufacturing process and ultimately on the glass properties have been investigated. Glasses in a range of compositions have been made and tested in the form of small samples as well as larger blocks of size 2×3×14 cm 3. Results of measurements on these materials, using a high energy particle beam, are presented.

Sensitized Up-Conversion Luminescence of Ho^(3+) in Nd^(3+)-Yb^(3+)-Ho^(3+) Co-doped ZrF_4-Based Glass

Up-conversion processes for the blue, green and red emissions were foundtwo-photon phenomenon, known as the cooperative phenomenon. This phenomenon was assisted by Nd^(3+)→ Yb^(3+) → Ho^(3+) energy transfer. The strong green emission due to the Ho^(3+) : (~5F_4, ~5S_2)→ ~5I_8 transitions was observed in Nd^(3+) - Ho^(3+) co-doped ZrF_4-based fluoride glasses under800 nm excitation. As an attempt to enhance Ho^(3+) up-conversion luminescences in the Nd^(3+) -Ho^(3+) co-doped ZrF_4-based glasses, Yb^(3+) ions were added to the glasses. As a result it wasfound that, in 800 nm excitation of 60ZrF_4. 30BaF2. (8-x)LaF_3. 1NdF_3. xYbF_3. 1HoF_3 glasses (x =0 to 7), sensitized up-conversion luminescences are observed at around 490 nm (blue), 545 nm(green), and 650 nm (red), which correspond to the Ho^(3+) : ~5F_3 → ~5I_8, ( ~5F_4, ~5S_2) →~5I_8 and ~5F_5 → ~5I_8 transitions respectively. The intensities of the green and red emissions ina 3 mol% YbF_3-containing glass were about 50 times stronger than those glasses without YbF_3. Thisis based on sensitization due to Yb^(3+) ions. In particular, the green emission was extremelystrong and the Nd^(3+) - Yb^(3+) - Ho^(3+) co-doped ZrF_4-based glasses have a high possibility ofrealizing a green up-conversion laser glass. In this paper the up-conversion mechanism in theglasses is discussed in detail.

Treatment method of hazardous pickling sludge by reusing as glass–ceramics nucleation agent

Heavy metal containing pickling sludge（PS） is one of the by-products of the stainless-steel-making industry,which has been considered hazardous due to contained chromium and nickel.Traditional methods of PS disposing are landfill and cement solidification.This research is aimed at disposing PS by solidification/stabilization and reusing it as a nucleation agent of glass–ceramics.The crystallization behavior and the properties of a glass in the CaO–MgO–SiO2–Al2O3 system were studied by considering PS as the nucleation agent.Experimental results confirm that introducing 14 wt% PS as the nucleation agent of glass–ceramics can decrease crystallization temperature by 110.8 °C,refine the grain size by forming isometric crystals with size of 2 lm,enhance Vickers hardness by 2690 MPa and decrease water absorption from（1.21 ± 0.10） wt% to（0.04 ± 0.01） wt%.Therefore,it is reasonable to conclude that PS can be utilized as a nucleation agent to improve the crystallization and mechanical properties of the glass–ceramics.The testing results of US EPA toxicity characteristic leaching procedure（TCLP）confirm the safety of this reusing method.