Radiative and radiationless processes of Er3+ in MnF2

We have designed a method for the measurement of radiative and radiationless transition rates of fluorescent systems with several metastable levels. This method applies to systems with adjacent metastable levels connected by multiphonon relaxation processes. The measurements required are those of the integrated fluorescence intensities and decay times at different temperatures; no absorption or excitation measurements are required. We have applied this method to the study of the fluorescence of Er³⁺ in MnF₂. The knowledge of both radiative and non- radiative decays has allowed us to reconstruct the kinetics of the excitation and de-excitation processes and to find the dependence on temperature and energy gap of multiphonon relaxation processes in this system.