Judd–Ofelt and spectroscopic analysis of erbium ions co-doped with samarium ions in phosphate glasses environment

The influence of Er 3+ ions on the optical properties of phosphate glasses doped by a fixed concentration of Sm +3 ions had been investigated. Optical absorption studies were executed to estimate the energy gap and Urbach energy. Judd–Ofelt, J–O, model has been applied to the absorption peaks for Er 3+ (4f 11 ) transitions to determine the J–O intensity parameters Ω t (t = 2, 4, 6). Using the calculated J–O parameters, the radiative transition probabilities (A r ), Branching ratios (B r ), and radiative lifetime (τ r ) of various excited states of Er 3+ ion have been calculated. The studied photoluminescence spectra under an ultraviolet excitation wavelength (380 nm) showed several visible emission bands confirming the down-conversion process. Energy transfer (ET) from 4 S 3/2 (Er 3+) to 4 G 5/2 (Sm +3 ) was affirmed. An intensive green emission peak due to 4 S 3/2 → 4 I 15/2 transition had been observed with stimulated emission cross-section of 7 × 10 –21 cm 2 . Graphical abstract