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

The influence of Er3+ 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 Er3+ (4f11) transitions to determine the J–O intensity parameters Ωt (t = 2, 4, 6). Using the calculated J–O parameters, the radiative transition probabilities (Ar), Branching ratios (Br), and radiative lifetime (τr) of various excited states of Er3+ 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 4S3/2 (Er3+) to 4G5/2 (Sm+3) was affirmed. An intensive green emission peak due to 4S3/2 → 4I15/2 transition had been observed with stimulated emission cross-section of 7 × 10–21 cm2. [ABSTRACT FROM AUTHOR]