Spectroscopic analyses of Er3+/Yb3+ co-doped laser sintering silica glasses

In this study, the laser sintering technique was used to obtain Er3+/Yb3+ co-doped silica glasses for up-conversion (UC) luminescence for the first time. Further, structural analysis of the glass sample was conducted via XRD, SEM and EDS measurements. Based on the measured absorption spectrum, important spectroscopic parameters including three intensity parameters omega t (t = 2, 4 and 6), theoretical and experimental line strengths, spontaneous transition probabilities, branching ratios and radiative lifetimes, were calculated using the Judd-Ofelt (J-O) theory. The UC properties of Er3+/Yb3+ co-doped silica glasses were investigated upon the excitation of a 976 nm laser. It has been experimentally confirmed that the green and red UC luminescences corresponding to the radiative transitions of Er3+: H-2(11/2) -> I-4(15/2) (green), S-4(3/2) -> I-4(15/2) (green) and F-4(9/2) -> I-4(15/2) (red) were achieved. This result is consistent with those of the J-O theoretical analysis. Additionally, the energy transfer mechanism between Er3+ and Yb3+, which is responsible for the UC process, was discussed based on their dependence on the pump power. The obtained results indicated that the Er3+/Yb3+ co-doped silica glasses manufactured using the laser sintering technique can be promising for the application of short-wavelength lasers.