Absorption and emission characteristics of Er 3+ ions in alkali chloroborophosphate glasses

Abstract

Alkali chloroborophosphate glasses containing 1 mol% of Er 3+ ions were studied experimentally using the absorption and emission spectroscopy. The energy level scheme for the 4f 11 (Er 3+) electronic configuration was deduced from the observed band energies of the absorption spectra in terms of a parametrized Hamiltonian using the various free-ion spectroscopic parameters. Oscillator strengths ( f) measured from the absorption spectra have been analyzed using the Judd–Ofelt theory to evaluate the three intensity parameters Ω λ ( λ=2, 4 and 6). Reasonable agreement between the measured and calculated f values has been found. Electric and magnetic dipole transition probabilities, fluorescence branching ratios, integrated emission cross sections and radiative lifetimes were calculated for all the excited states of Er 3+ ions. The non-radiative (W NR) relaxation rates from the excited levels to the next lower levels have been calculated and the relationship between the energy gap and non-radiative relaxation rate has been established. These results were used to predict the possible potential laser transitions in Er-doped alkali chloroborophosphate glasses.