[Influence of K+ and Al3+ on the optical properties of Er3+ doped Sol-gel derived silica glasses].

Al3+ and K+ ions were introduced in Er(3+) -doped silica glass successfully through Sol-gel route. The optical characterizations including absorption spectra, transmission spectra, photofluorescence spectra, up-conversion spectra, Raman spectra and fluorescence decay lifetime were undertaken on the samples. The results show that not only the fluorescence intensity was strenthened by more than 20 and 70 times, but also the lifetime of Er3+ ions in Al(3+) -doped and K+ and Al(3+) -codoped samples was prolonged to 7.1 and 11.2 ms from 4.8 ms, respecticely. And by analysing the results, the authors concluded that the influences of Al3+ and K+ on Er3+ ions are completely different. And the authors found that Er3+ ions in silica glass may have two up-conversion mechanisms: two-phonon absorption and energy-transfer up-conversion using 980 nm excitation.