Ultrafast Yb:CALGO laser oscillator based on cross-polarization pumping with a cost-efficient multi-mode diode

We demonstrate a multimode diode-pumped Yb:CALGO laser oscillator based on bandwidth-optimized cross-polarization pumping targeting sub-30-fs operation. In our first proof of principle experiment we achieved mode-locked operation at 83 MHz repetition rate with 0.4 W of average power and a 33-nm-bandwidth optical spectrum supporting sub-40-fs pulses. This concept offers a simple and cost-efficient alternative to green-pumped Ti:sapphire lasers.