Diode-pumped laser operation at 1053 and 900 nm in Sr1−xLax−yNdyMgxAl12−xO19 (Nd:ASL) single crystal

Abstract

Neodymium-doped strontium lanthanum magnesium aluminoxide (Sr1−xLax−yNdyMgxAl12−xO19, Nd:ASL) single crystals were grown by the Czochralski technique. Branching ratios for both transitions 4F3/2→4I9/2 (900 nm) and 4F3/2→4I11/2 (1053 nm) were calculated to be 45% by the Judd–Ofelt theory based on polarized absorption spectra of Nd3+. The spectroscopic quality factors (X = Ω4/Ω6) of X = 0.87 for σ polarization and X = 1.55 for π polarization were calculated for 7 at.% Nd:ASL crystal. Quantum efficiency was calculated to be 74%. Laser operation was pumped by a 792 nm LD source. By adopting 7 at.% Nd:ASL crystal as gain media, output power of 5.7 W and slope efficiency of 50% were obtained at 1053 nm with output coupler T = 9.79% and achromatic lens focus of 75 and 150 mm. Output power of 6.9 W and slope efficiency of 36% at 1053 nm, together with output power of 1.72 W and slope efficiency of 17% at 900 nm were obtained in 5 at.% Nd:ASL crystal.