An investigation of the optical properties of Nd3+ ions in alkali tellurofluorophosphate glasses

Absorption and fluorescence spectra of Nd3+-doped alkali tellurofluorophosphate glasses with molar compositions of 50(NaPO3)6 + 10TeO2 + 20AlF3 + 19RF + 1Nd2O3 (R = Li, Na and K) have been recorded and analyzed. Judd–Ofelt analysis has been accomplished for the measured oscillator strengths to calculate different optical parameters such as Judd–Ofelt intensity parameters Ωλ (λ = 2, 4 and 6), radiative transition probabilities (AR), branching ratios (βR) and radiative lifetimes (τR). In order to ascertain the efficiency of these glasses for device applications, the values of quantum efficiencies (η) and non-radiative relaxation rates (WNR) of the 4F3/2 emission level due to multiphonon relaxation is obtained from the measured and calculated lifetimes. Branching ratio calculations also indicate that the 4F3/2 → 4I11/2 transition has the potential for laser applications. From the measured near infrared luminescence spectra, the peak stimulated emission cross-section (σe) values were evaluated for selected laser transitions. The relatively high values of σe obtained for Nd3+ in alkali tellurofluorophosphate glasses suggest that these materials can be considered as candidates for optical device applications.