SESAM mode-locked Tm:Y₂O₃ ceramic laser

We demonstrate a widely tunable and passively mode-locked Tm:Y₂O₃ ceramic laser in-band pumped by a 1627-nm Raman fiber laser. A tuning range of 318 nm, from 1833 to 2151 nm, is obtained in the continuous-wave regime. The SESAM mode-locked laser produces Fourier-transform-limited pulses as short as 75 fs at ∼ 2.06 µm with an average output power of 0.26 W at 86.3 MHz. For longer pulse durations of 178 fs, an average power of 0.59 W is achieved with a laser efficiency of 29%. This is, to the best of our knowledge, the first mode-locked Tm:Y₂O₃ laser in the femtosecond regime. The spectroscopic properties and laser performance confirm that Tm:Y₂O₃ transparent ceramics are a promising gain material for ultrafast lasers at 2 µm.