Probing of the oxygen-related defects response in Nd:phosphate glass within self-action of the laser radiation technique

Abstract

Mixed barium‑strontium Nd:phosphate glasses of composition: 58P2O5–13K2O–8Al2O3–4B2O3–2.5La2O3–2SiO2–0.5Nd2O3–12(Ba1–xO/SrxO) with a different degree of molar substitution x were prepared. Optical properties of these glasses were examined by UV–Vis-IR and photoluminescence (PL) spectroscopies. Considering IR spectra, it was suggested a certain contribution of oxygen defects in the optical properties of glasses. UV–Vis absorbance and PL emission spectra owing to the internal f–f electron transitions of Nd3+ ions were shown a complex character of electronic processes. The result of a comprehensive analysis of the optical scattering indicatrices has revealed non-monotonic variations of the scattering efficiency against the ratio of Sr to Ba that is correlated with the suggested content of the oxygen defects in the mixed glasses. A cubic nonlinear optical (NLO) response under the pulsed laser radiation self-action at 1064 nm shows that the self-defocusing effect increases with the molar fraction of Ba. For a continuous wave laser excitation at 1064 nm, the most efficient NLO refractive response with Re(χ(3)) = 2.9 × 10−3 esu was obtained in the pure strontium Nd:phosphate glass, being classified as a promising for NLO applications.