Dependence of spontaneous emission and nonradiative relaxations of Tm3+ and Er3+ on glass host and temperature

Abstract

Radiative transition probabilities from 3 P 0, 1 I 6, 1 D 2, and 1 G 4 levels of Tm3+ in glasses were calculated using the matrix elements obtained by intermediate coupling scheme and experimentally obtained intensity parameters. In the absence of self‐absorption of fluorescence by the glass host, the fluorescence intensities of Tm3+ and Er3+ increase in the order borate < phosphate < germanate < tellurite. Nonradiative transition probabilities in different glass hosts from 1 D 2 to 1 G 4 levels of Tm3+ and from 4 S 3/2 to 4 F 9/2 and from 4 F 9/2 to 4 I 9/2 levels of Er3+ were calculated. The nonradiative transition rates follow the formula W N R = W (0) exp(−αp), where p is the number of phonons matching the energy gap. The nonradiative transition rates of Er3+ exhibit temperature dependence consistent with the multiphonon relaxation theory. In Tm3+ the temperature dependence of nonradiative relaxation rates is complicated by the existence of self‐absorption and transfer of energy from matrix to Tm3+. Based on the above results, quantum efficiencies of luminescence of rare earth in glasses can be predicted.