Optical spectroscopy of Nd-doped borate glasses

Optical absorption, luminescence excitation and emission spectra as well as luminescence kinetics of the Nd³⁺ centres in glasses with Li2B4O7:Nd, LiCaBO3:Nd, and CaB4O7:Nd compositions containing 0.5 and 1.0 mol. % Nd2O3 have been investigated and analyzed. Using Judd-Ofelt theory oscillator strengths (f) and phenomenological intensity parameters Ωt (Ω2, Ω4, and Ω6) for all investigated glasses were determined. Radiative transitions rates (Wr), radiative lifetimes (τrad), and branching ratios (β) for Nd³⁺ centres have been calculated. Measured lifetimes for Nd³⁺ centres in the ⁴F3/2 emitting level are compared with those calculated and quantum efficiency (η) have been estimated.