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 E r 3 + -doped yttrium gallium garnet crystal, Y 3 G a 5 O 12 (YGG), are studied. The stimulated emission cross section is 1.4 × 10 − 21 c m 2 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.