Simulation of the optical properties of Tm:ZBLAN glass. II. Energy transfer between Tm3+ ions under single- and dual-wavelength excitation

The energy transfer rate between Tm3+ ions in ZBLAN glass was estimated from the optical spectra and transition rates on the basis of a method proposed by Kushida. The optical spectra and radiative transition rates were obtained from the structural models prepared by molecular dynamic simulation and the crystal field theory. The lifetimes of 3H4, 1G4 and 1D2 levels were estimated from the calculation and the results were experimentally confirmed. The numerical model was also used to predict emission intensities under dual-wavelength excitation and decay curves under CW excitation.