Excited state absorption cross sections of 4I13/2 of Er3+ in ZBLAN

Optical transition intensity parameters of Er3+ in ZBLAN were carefully calculated, and the obtained results were compared with those reported by others. The emission cross sections of 4S3/2 → 4I13/2 and 4I11/2 → 4I13/2 transitions were confirmed according to the Fuchtbauer–Ladenburg (FL) formula. The excited state absorption cross sections for 4I13/2 → 4S3/2 and 4I13/2 → 4I11/2 transitions were derived by using the reciprocity relationship in the framework of McCumber theory. The laser gain properties of 4S3/2 → 4I13/2 and 4I11/2 → 4I13/2 transitions were discussed.