Variations in the oscillator strength of the 7F0→5D0 transition in Eu3+:Y2SiO5 single crystals

We report on the low temperature properties of the F07→D05 transition in Eu3+:Y2SiO5 in a series of single crystals grown under different conditions. Inhomogeneous linewidths, peak absorption coefficients and homogeneous linewidths have been determined for ions in the two sites of the crystalline structure. Unexpected and strong variations of the peak absorption coefficients are observed for ions in site 1, but not in site 2. We attribute this effect to a combination of changes in inhomogeneous broadening and oscillator strength.