Continuous-wave and femtosecond laser operation of Yb:CaGdAlO_4 under high-power diode pumping

We demonstrate the generation of $68\mathrm{fs}$ secant hyperbolic pulses at a $105\mathrm{MHz}$ repetition rate with an average power of $520\mathrm{mW}$ from a diode-pumped ${\mathrm{Yb}}^{3+}:\mathrm{Ca}\mathrm{Gd}\mathrm{Al}{\mathrm{O}}_4$ mode-locked laser. A semiconductor saturable absorber allows passive mode locking, and a $15\mathrm{W}$ diode laser is used to pump directly the crystal. To our knowledge this represents the highest average power ever obtained for a sub-$100\mathrm{fs}$ diode-pumped Yb-bulk laser.