High-efficiency Er-doped yttrium gallium garnet laser resonantly pumped by a laser diode at 1.47  µm

The spectroscopic and laser properties of an Er³⁺-doped yttrium gallium garnet crystal, Y₃Ga₅O₁₂ (YGG), are studied. The stimulated emission cross section is 1.4×10^-21cm² at 1.65 µm. A continuous-wave laser resonantly pumped by a laser diode at 1.47 µm is demonstrated, delivering a maximum output power of 3.34 W. Benefiting from the low phonon energy of the YGG host, the corresponding slope efficiency is as high as ∼42%. To the best of our knowledge, this is the highest slope efficiency from the laser-diode resonantly pumped Er lasers at room temperature in the 1.6 µm spectral range.