Differential absorption measurements of Cr4+-doped forsterite under picosecond excitation

Polarized differential absorption spectra of Cr4+- doped forsterite have been studied using a picosecond pump- probe technique. For pump beam and probe beam polarization parallel to the axis, an excited state absorption in the 450-800 nm region is observed and assigned to the 3T2yields3T1(3P) transition of Cr4+ ion. The lifetime of the 3T1(3F) state is estimated to be less than 15 ps.