Mode-locking of anisotropic Tm,Ho:GdScO₃ laser delivering 57-fs pulses at 2078 nm

We report on a SESAM mode-locked bulk laser in the 2 µm spectral range employing a novel Tm,Ho-codoped orthorhombic perovskite crystal, which delivers sub-100 fs pulses with polarization along all three different crystallographic axes. With the polarization along E//b, the shortest pulse of 57 fs is achieved at 2078 nm without any additional dispersion elements, corresponding to an average power of 202 mW at 86.6 MHz repetition rate. The present result shows the potential of anisotropic Tm,Ho co-doped GdScO₃ crystal for generating ultrashort pulses around 2 µm.