Lead Fluoroborate Glasses Research Articles

Lead fluoroborate glasses doped with Nd3+

Results of absorption, emission and fluorescence lifetime (for the 4F3/2→4I11/2 transition) are presented for a new lead fluoroborate glass doped with different concentrations of Nd2O3 varying from 0.04 up to 3.49wt%. The calculated Judd–Ofelt parameters are: (1.7±0.1)×10−20cm2, (3.4±0.3)×10−20cm2, (3.6±0.3)×10−20cm2. Branching ratios calculations show that the 4F3/2→4I11/2 transition has the most potential for laser applications. The best spectroscopic performance was obtained for the sample doped with 1.75wt% of Nd2O3: emission cross-section of 3.6×10−20cm2 at 1060nm, fluorescence lifetime of 0.06ms and effective fluorescence bandwidth of 30.43nm. The samples have high refractive index of 2.2 and a density of about 6.9g/cm3. Concentration quenching was observed at 3.49wt%. The results obtained suggest that this new material can be considered as an interesting candidate for laser applications with similar properties when compared to other known glasses used as laser media.

Spectroscopic properties of lead fluoroborate glasses codoped with Er^3+ and Yb^3+

Energy transfer at 1500 nm in lead fluoroborate glasses (PbO–PbF2–B2O3) codoped with Er3+ and Yb3+ is studied for the first time to the authors’ knowledge. A sample codoped with 1 mol. % of Yb2O3 and 0.01 mol. % of Er2O3 has a measured fluorescence lifetime of (1.30±0.07) ms and an energy transfer efficiency of 80%. Also, a large emission band, of 72.4 nm has a measured peak emission cross section of (0.73±0.06)×10-20cm2. The calculated Judd–Ofelt parameters are Ω2=(3.51±0.14)×10-20 cm2,Ω4=(1.09±0.07)×10-20 cm2, and Ω6=(0.94±0.07)×10-20 cm2. The temporal evolution of the Yb3+ fluorescence is fitted by use of the Yokota–Tanimoto expression to yield the Yb3+ diffusion constant [(1.6±0.2)×10-10 cm2 s-1] and the critical radius of Yb3+/Er3+(18±1)×10-8 cm. Results with the singly doped samples produced are presented to clarify the energy transfer process.

Lead fluoroborate glass doped with ytterbium

Absorption and luminescence spectra were measured in a new ytterbium-doped lead fluoroborate glass. The best spectroscopic performance was obtained for the concentration of 1.153×10 20 ions/cm 3 of Yb 3+: emission cross-section of 1.07×10 −20 cm 2 at 1022 nm, fluorescence lifetime of 0.81 ms, and high absorption cross-section (2.57×10 −20 cm 2) at the absorption peak wavelength (976 nm). The lifetime is shortened with the increase of the Yb 3+ concentration and decreases to 0.09 ms for 10.6×10 20 ions/cm 3. The results suggest that this material can be considered an interesting candidate for laser applications as it has very similar properties when compared to other known glasses used as laser media.

Spectroscopic properties of lead fluoroborate and heavy metal oxide glasses doped with Yb 3+

A new glass of heavy metal oxide (25.0Bi 2O 3–57.0PbO–18.0Ga 2O 3 (mol%)) doped with Yb 3+ is presented and compared with lead fluoroborate glass (43.5H 3BO 3–22.5PbCO 3–34.0PbF 2 (mol%)), also doped with ytterbium. The interest in Yb 3+ for laser action and short pulse generation under diode pumping has been reported in the literature. Spectroscopic properties were studied for both glasses doped with 0.5 mol% of Yb 2O 3. The absorption cross-section of the heavy metal oxide glass is (2.20±0.15)×10 −20 cm 2 at the absorption peak wavelength of 968 nm and its emission cross-section is (0.75±0.05)×10 −20 cm 2 at the extraction wavelength of 1012 nm. A fluorescence effective linewidth of 86 nm and a fluorescence lifetime of 0.40 ms were measured. In the case of the lead fluoroborate glass used for comparison, these values change to (2.56±0.18)×10 −20 cm 2 (absorption cross-section), (1.07±0.08)×10 −20 cm 2 (emission cross-section at 1022 nm), 60 nm (fluorescence effective linewidth) and 0.81 ms (fluorescence lifetime). Calculations of the minimum pump intensity are also presented. Both have spectroscopic properties for laser applications that are similar to those of other known glasses (phosphate and tellurite laser glasses) used as active laser media. The large emission bandwidth measured for the heavy metal oxide is of interest for tunable lasers.

Spectroscopic properties of lead fluoroborate glasses doped with ytterbium

A new lead fluoroborate glass (PbO-PbF2-B2O3) doped with ytterbium (Yb:PbFB) is presented. Samples with different concentrations of Yb3+ were produced and had their emission cross-sections, fluorescence lifetimes and minimum pump intensities determined. They have high refractive index of 2.2 and a density of 4.4 g/cm3. For a doping level of 1.153x1020 ions/cm3, the fluorescence lifetime, after excitation at 968 nm, is 0.81 ms, which is comparable to Yb:tellurite laser glass. Also, an emission band at 1022 nm is measured with emission cross-section of approximately 1.07x10-20 cm2 and fluorescence effective linewidth of 60 nm, which is comparable to Yb:phosphate laser glass.

Optical properties of Sm 3+ doped lead fluoroborate glasses

We present a study of emission, absorption and vibrational properties of Sm 3+ doped lead fluoroborate glasses (PbO–PbF 2–B 2O 3–Sm 2O 3) as a function of the Sm 3+ content. Changes in the position and the intensity parameters of the transitions are closely related to structural changes in the glass network. A Judd–Ofelt scheme was used to estimate the intensity parameters Ω λ and radiative properties for Sm 3+ in the glass. The behaviour of Ω 2 and Ω 6 parameters suggested a decrease in the asymmetry degree of the local ligand field at Sm 3+ sites and an increase in the covalency of Sm–O bond, respectively. This hypothesis was verified by analysing the structural role of Sm 2O 3 through Raman and infrared spectroscopy measurements.

X-ray photoelectron spectroscopy and ionic transport studies on lead fluoroborate glasses

Fast-anion-conducting glasses in the system xPbF2:(1-x)B2O3 have been synthesized and analysed by thermal, electrical and spectroscopic techniques. The ionic conductivity ( sigma ) of these glasses is measured as a function of temperature and chemical composition by the complex impedance method and the results indicate that the conduction of fluorine as charge carriers is governed by activation energy alone. Infrared and X-ray photoelectron spectroscopy studies have provided evidence for fluorine participation in the berate network. Further, the compositional dependence of X-ray photoelectron F 1s spectra indicates that fluorine is incorporated predominantly as B-O-F and Pb-O-F bonds in the oxide network at high B2O3 and PbF2 content respectively. The spectroscopic results obtained are discussed in relation to anionic conduction.

Properties and structure of PbO-PbF2-B2O3 glasses

Glasses containing as little as 5 mol % B2O3 have been made in the ternary system PbO-PbF2-B2O3. Glass transformation and crystallization temperatures, thermal expansion behavior, and electrical conductivity of these glasses have been measured. The lead fluoroborate glasses appear to be anion conductors, with conductivities among the highest ever reported for fluorine-conducting glasses. A model for the structural role of fluorine in these glasses is proposed.

X-ray photoelectron spectroscopic study of lead fluoroborate glasses

Etude des spectres XPS F 1s , Al 2p et B 1s afin de mieux comprendre l'etat du fluor dans les verres de fluoroborate de plomb. Etude des verres de composition: 30B 2 O 3 •(70-x)PbO•xPbF 2 (x=5, 15, 25 mol%) et 10B 2 O 3 •20AlF 3 •(70-x)PbO•xPbF 2 (x=20, 40, 60 mol%). Le deplacement chimique du spectre F 1s est etudie d'apres la densite electronique au niveau des ions fluorures et est correle a la force, de type simple liaison, des liaisons B-F, Al-F et Pb-F

Lead fluoroborate glasses

Glasses containing up to 60-mol % PbF2 have been made in the binary system PbF2-B2O3. The glass transformation and crystallization temperatures, thermal expansion behavior, and electrical conductivity of these glasses have been measured. A corresponding series of lead borate glasses were also studied to provide a basis for comparison of the effects of fluorine and oxygen on the properties of these glasses. The lead fluoroborate glasses appear to be anion conductors, with conductivities approaching the highest ever reported for fluorine conducting glasses.