2-W continuous-wave and passively Q-switched Tm,Ho:YLF channeled waveguide laser at 2.05 µm

We report on the operation of an efficient Tm,Ho:YLF depressed cladding, channeled waveguide laser in both continuous-wave (CW) and passively Q-switched (PQS) regimes, producing laser emission at the wavelength of 2.05 µm. The 70-µm diameter depressed cladding waveguide, fabricated using femtosecond laser inscription, had a low propagation loss value of 0.14 dB/cm and a refractive index contrast of 8.3 × 10^-4. In the CW regime, the waveguide laser was excited at 780 nm, and an output power of up to 2 W was generated at the incident pump power of 4.14 W with a power slope efficiency of 50.0%. PQS operation was further realized by utilizing a Cr:ZnSe saturable absorber (SA), whereby the waveguide laser generated as short as 19.6-ns pulses with a power slope efficiency of 18.9%.