Novel Er-doped PbO and B2O3 based glasses:: investigation of quantum efficiency and non-radiative transition probability for 1.5 μm broadband emission fluorescence

Er3+-doped PbO:B2O3, PbO:Ga2O3:B2O3, PbO:Bi2O3:B2O3 and PbO:Ga2O3:Bi2O3:B2O3 showing broadband 1.5 mum absorption and emission are reported and their emission spectra, radiative, non-radiative transition probabilities, fluorescence lifetime, and their quantum efficiency were studied. It was found that glasses with high refractive index (1.78-1.94) had high spontaneous transition probability A(j'j) (172.93-245.98 s(-1)). FT-IR spectra for such glasses were carried out in order to investigate their vibration frequency and phonon energy. The phonon energy for such glasses (1375-1200 cm(-1)) decreased with increasing PbO content. The multiphonon relaxation for all glass samples was not a dominating factor for the non-radiative transition process. The high non-radiative transition rates (254.02-613.32 s(-1)) therefore should be due to energy transfer to the impurities (OH groups) and cross-relaxations in these glasses, which can be minimized. (C) 2003 Elsevier B.V. All rights reserved.