Temperature and pressure dependence of the homogeneous width of 7F0–5D0 electronic transition in Sm2+-doped sodium borate glass

The homogeneous width Γh of 7F0↔5D0 transition in Sm2+ ions doped into sodium borate glass was determined at T=5–293 K under P=1 bar and at T=5, 80 and 120 K under various P up to 8 kbar. The line width Γh was obtained from spectral hole burning (SHB) and time-resolved resonant fluorescence line narrowing (FLN) experiments. It was found that at P=1 bar the T-dependence of Γh changes from Γh(T)∝T2 (quadratic) for T<20 K to Γh(T)∝T (linear) for T>20 K. Under pressure, Γh grows slightly at all three T values studied (at 80 K by 1.2%/kbar and at 120 K by 1.6%/kbar in the range 0–8 kbar). Possible mechanisms to explain the observed T- and P-dependences of Γh are briefly discussed.