  In this work, we demonstrate post-compression of 1.2 picosecond laser pulses
to 13 fs via gas-based multi-pass spectral broadening. Our results yield a
single-stage compression factor of about 40 at 200 W in-burst average power and
a total compression factor >90 at reduced power. The employed scheme represents
a route towards compact few-cycle sources driven by industrial-grade Yb:YAG
lasers at high average power.
