Abstract
The melt quenching method is used to prepare tellurite glasses co-activated with erbium ions and silver nanoparticles (Ag NPs). The glass samples are characterized by x-ray diffraction, UV-vis-NIR absorption, transmission electron microscopy (TEM) imaging, and photoluminescence spectroscopy. The XRD pattern shows no sharp peak indicating an amorphous nature of the glasses. The presence of Ag NPs is confirmed from TEM micrograph. The absorption spectra reveal not only the peaks due to Er3+ ions, but also the surface plasmon resonance band of silver NPs in the 510-535 nm range. The J-O model has been applied to the room temperature absorption intensities of Er3+ (4f(11)) transitions to establish the so-called J-O intensity parameters: Omega(2), Omega(4), and Omega(6). The intensity parameters are used to determine the radiative decay rates (emission probabilities of transitions) and branching ratios of the Er3+ transitions from the excited state J manifolds to the lower-lying J' manifolds. Intensified of 1.53 mu m band is obtained for the sample containing 0.5 mol.% of AgNO3 (Ag0.5 glass) using for excitation a laser operating at 980 nm. The simultaneous influence of the Ag NPs > Er3+ energy transfer and the contribution of the intensified local field effect due to the silver NPs give origin to the enhancement of both the Photoluminescence (PL) intensity and the PL lifetime relative to the I-4(13/2) > I-4(15/2) transition, whereas the quenching is ascribed to the energy transfer from Er3+ ions to silver NPs. Based on the analysis of the temperature dependence of the PL intensity and decay time, we identified a weak back transfer process from Er to the glass host that makes the quenching of the PL intensity weak. Large magnitudes of calculated emission cross-section (sigma(e)), effective bandwidth (Delta lambda(eff)), and bandwidth quality factor (FWHM x sigma(e)) relatives to I-4(13/2) > I-4(15/2) transition in Er doped Ag0.5 glass have been shown. They indicate that this glass sample has good prospect as a gain medium applied for 1.53 mu m band broad and high-gain erbium-doped fiber amplifiers. (C) 2015 AIP Publishing LLC.