A Resonantly Pumped 1645 nm Er:YAG Nonplanar Ring Oscillator With 10.5 W Single Frequency Output

We demonstrate a single frequency Er:YAG nonplanar ring oscillator (NPRO) resonantly pumped by a fiber laser. Up to 10.5 W single frequency laser output with a slope efficiency of 60.03% was achieved by optimizing the parameters of the Er:YAG NPRO. At 10.5 W output power the
M
²
-factors of the Er:YAG NPRO were 1.09 and 1.24 in the
x
- and
y
- directions, respectively. The linewidth of the Er:YAG NPRO was 18.6 kHz.