Dual-wavelength synchronous operation of a mode-locked 2-μm Tm:CaYAlO_4 laser

We experimentally demonstrated dual-wavelength synchronous operation of a high-power passively mode-locked 2-μm Tm:CaYAlO4 (Tm:CYA) disordered crystal laser with semiconductor saturable absorber mirror (SESAM) as mode locker. The mode-locked laser emitted an average output power as high as 830 mW with pulse duration of 35.3 ps and repetition rate of 145.4 MHz. The mode-locking dual wavelengths were centered at 1958.9 nm and 1960.6 nm, respectively. Autocorrelation trace clearly shows beating pulses with pulse width of 3.5 ps and repetition rate of 0.13 THz.