RESUMO
Microcline feldspar crystal has been analyzed in order to determine the centers suitable for use in ESR and luminescence dating. ESR measurements at RT showed the Fe3+ line, and at 77K the Si-O(-) ..X signal with g=2.0052, 2.0098 and 2.0128. TL glow peak at 157 and 300 degrees C in UV interval were observed and in the VIS range we noted peaks at 150, 280 and 340 degrees C. TL growth curve of the 340 degrees C peak could be fitted by a saturating exponential equation and can be used in TL dating. Emission curves showed band widths 1.95+/-0.09, 2.73+/-0.08 and 4.94+/-0.50 eV. Transitions from 4T1-->6A1)of Fe3+ can be associated with the 1.95 eV band and the transition from 4A1 4E(G)-->6A1(S) with 2.73 eV band.
RESUMO
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.
RESUMO
The optical properties of a new family of neodymium doped BPG (Bi2O3-PbO-Ga2O3 ) glasses are presented. We measured a high refractive index, of 2.5, and a transmission cutoff in the far infrared at 8microm. Three intense emission bands are observed centered at 877nm, 1066nm and 1341nm. The emission cross-section is 10 -20 cm 2 and the total spectral linewidth is 30nm at 1066nm. The Judd-Ofelt parameters are calculated and used to evaluate transition probability, radiative lifetime and branching ratios. The optical properties of these Nd:BPG glasses show promise for their use as a new active laser material.
