Spectral hole burning and fluorescence in femtosecond laser induced Sm2+-doped glasses

The femtosecond laser was used to irradiate sol–gel derived Sm3+-doped Al2O3–SiO2 glasses, in which the Sm3+ was reduced into Sm2+ ions. The fluorescence line narrowing was applied to investigate the coordination sphere of the Sm2+ ion. The spectral hole burning was performed on 7F0→5D0 transition of the Sm2+. The depth and width of the burnt holes were ∼27% and ∼4 cm−1 FWHM at 7 K, respectively. Hole spectra were stable up to room temperature. The hole-burning efficiency was superior to that of Sm2+ in H2 treated glasses and comparable to that in X-ray in terms of hole-burning dynamics.