865814.fig.006a
(a)
865814.fig.006b
(b)
Figure 6: (a) Photoluminescence spectra of Fe-MG SiO2 glasses (F1M4, F2M4, F3M4, and F4M4) and M4 glass. (b) Variation of photoluminescence intensity with molar concentration of Fe-I in F M4 glasses ( ).