MXene Ti3C2Tx saturable absorber for passively Q-switched mid-infrared laser operation of femtosecond-laser–inscribed Er:Y2O3 ceramic channel waveguide

We report on an Er:Y2O3 ceramic channel waveguide laser operating at continuous-wave and passively Q-switched regimes, for the first time to the best of our knowledge. The Er:Y2O3 ceramic channel waveguide has been fabricated by a femtosecond laser direct-writing technique. The maximum output power reached 123.5 mW in continuous-wave mode with a slope efficiency of about 21%, and the lasing behavior has been found simultaneously at 2710.28, 2716.76, and 2723.18 nm. We have further fabricated an MXene Ti3C2Tx saturable absorber mirror to operate the Er:Y2O3 waveguide in passively Q-switched regime. At the same time, property of the MXene Ti3C2Tx saturable absorber has been characterized, and nonlinear saturable absorption of the saturable absorber has also been measured. The average output power is about 67.6 mW, and the shortest pulse width is about 58.1 ns. This work indicates that femtosecond laser direct writing is a reliable technique for processing mid-infrared ceramic waveguides, and MXene Ti3C2Tx is promising for operating pulsed mid-infrared lasers.