Efficient CW Dual-Wavelength and Passively $Q$ -Switched Tm:LuAG Lasers

Efficient diode-pumped Tm:LuAG lasers operating in continuous wave, dual-wavelength,and passive
$Q$
-switching regimes have been demonstrated. A maximum output power of 4.42 W with a beam quality of
$\mathrm{M}^{\mathbf {2}}\le 1.45$
at 2021.2 nm was obtained, corresponding to a slope efficiency of 49.5%. Using a birefringent quartz plate, the Tm:LuAG laser emitted the highest output power of 2.3 W at dual-wavelength of 2022 and 2030 nm. With a SWCNT-SA employed as saturable absorber, passively
$Q$
-switched Tm:LuAG laser was realized, which generated the shortest pulses of 405 ns at 2021.6 nm and a maximum single pulse energy of
$40.6~\mu $
J at 2019.7 nm.