Direct generation of megawatt-peak-power sub-100-fs vector vortex beams from a Mamyshev fiber oscillator

We demonstrate a few-mode Yb-doped fiber Mamyshev oscillator that directly generates megawatt-level peak power femtosecond vector vortex beams. Mode selection is achieved via engineered mode- and polarization-dependent intracavity losses, enabling stable operation in the targeted spatial mode. The oscillator delivers radially and azimuthally polarized pulses with ~4.86 W average power and ~260 nJ pulse energy, externally compressed to 65 fs, corresponding to a ~2.9 MW peak power. First-order optical vortex pulses are also obtained with comparable energy and duration. These results represent, to our knowledge, the shortest pulses and highest peak powers reported for vector vortex beams generated directly from a fiber oscillator, advancing ultrafast structured-light sources for high-field and materials-processing applications.