Spectroscopic properties of lead fluoroborate and heavy metal oxide glasses doped with Yb3+

A new glass of heavy metal oxide (25.0Bi(2)O(3)-57.0PbO-18.0Ga(2)O(3) (mol%)) doped with Yb3+ is presented and compared with lead fluoroborate glass (43.5H(3)BO(3)-22.5PbCO(3)-34.0PbF(2) (mol%)), also doped with ytterbium. The interest in Yb3+ 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 Yb2O3, The absorption cross-section of the heavy metal oxide glass is (2.20 +/- 0.15) X 10(-20) cm(2) at the absorption peak wavelength of 968 nm and its emission cross-section is (0.75 +/- 0.05) X 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) X 10(-20) cm(2) (absorption cross-section), (1.07 +/- 0.08) X 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. (C) 2002 Elsevier Science B.V. All rights reserved.