1.2 μJ pulses with average power of 9 W were directly generated from a passively mode-locked picosecond oscillator based on a Nd:GdVO4 bulk crystal. Short cavity operation in continuous wave and mode-locking regimes was conducted first to confirm the resonator performance and proper alignment. With a carefully calibrated q-preserving multi-pass cell inserted into the laser cavity, the cavity length of the original short cavity was extended while the mode-matching condition was maintained fairly
