Judd–Ofelt analysis and radiative properties of the Sm3+ centres in Li2B4O7, CaB4O7, and LiCaBO3 glasses

Abstract

The spectroscopic and luminescence properties of a series Sm-doped Li2B4O7, CaB4O7, and LiCaBO3 borate glasses are investigated using optical absorption, photoluminescence, and decay kinetics techniques as well as Judd–Ofelt (J–O) analysis. Borate glasses of high chemical purity and optical quality, doped with Sm2O3 in amounts of 0.5 and 1.0mol.% were obtained from the corresponding polycrystalline compounds in the air atmosphere using standard glass synthesis technology. The J–O intensity parameters have been calculated using the spectral intensities of the Sm3+ absorption bands. Radiative properties such as transition probabilities, branching ratios, stimulated emission cross-sections, and radiative lifetimes are estimated for 4G5/2→6HJ (J=5/2, 7/2, 9/2, and 11/2) emission transitions of the Sm3+ ions. The luminescence kinetics of the Sm3+ centres are characterised by slightly non exponential decay with lifetime values, which depend on the basic glass composition and Sm impurity concentration. The measured lifetimes were compared with those calculated and quantum efficiencies have been estimated. The obtained high quantum efficiencies of emission transitions (∼70%) and high quantum yields of luminescence (∼14%) of the Sm3+ centres show that the investigated borate glasses belong to perspective luminescent and laser materials.