Spectroscopic Properties and Laser Performance of ${\hbox {Er}}^{3+}$ and ${\hbox {Yb}}^{3+}$ Co-Doped ${\hbox {GdAl}}_{3}({\hbox {BO}}_{3})_{4}$ Crystal

An Er:Yb:GdAl
₃
(BO
₃
)
₄
crystal was grown and room-temperature polarized absorption, emission, and gain spectra were investigated. Fluorescence decay curves of Er
³⁺
at 1530 nm and Yb
³⁺
at 1040 nm in the crystal were measured. Efficient laser operation of Er:Yb:GdAl
₃
(BO
₃
)
₄
crystal at 1.5-1.6 mum was realized. Quasi-continuous-wave output powers of 1.8 W with slope efficiency of 19% and 0.78 W with slope efficiency of 14% were achieved in diode-pumped c-cut and c-cut and a-cut crystals, respectively. The output spectrum and polarization of Er:Yb:GdAl
₃
(BO
₃
)
₄
laser were also investigated.