A method for the measurement of radiative-transition rates in rare-earth-doped laser crystals with several metastable levels is presented. The excited-state absorption in Er3+:YAlO3 is measured in a pump- and probe-beam experiment. With this information the populations of the metastable levels 4I13/2, 4I11/2, and 4S3/2 are derived. In combination with data of the relative fluorescence intensities and fluorescence-decay curves the radiative rates and quantum efficiencies of transitions from these levels are experimentally determined. The results are compared to data from a Judd-Ofelt analysis.
- IOMS-APD: Active Photonic Devices