Midinfrared laser source with high power and beam quality

A simple scheme for generation of high power in the midinfrared is demonstrated. By using a $15\text{\hspace{0.17em} W}$ thulium-doped fiber laser emitting at $1907\text{\hspace{0.17em} nm}$ to pump a Q-switched Ho:YAG laser, we obtained $9.8\text{\hspace{0.17em} W \hspace{0.17em} at \hspace{0.17em} 2096 \hspace{0.17em} nm}$ at a $20\text{\hspace{0.17em} kHz}$ pulse repetition rate with excellent beam quality. The output of this laser was used to pump a doubly resonant zinc germanium phosphide based optical parametric oscillator, and we obtained $5.1\text{\hspace{0.17em} W}$ average power in the $3–5\text{\hspace{0.17em} μm}$ range with $M^2\approx 1.8$.