106 W, picosecond Yb-doped fiber MOPA system with a radially polarized output beam.

We report the generation of high average output power, high peak power, and high pulse energy radially polarized picosecond pulses from a compact gain-switched laser-diode-seeded Yb-doped fiber master oscillator power amplifier (MOPA) system. A q-plate was employed as a mode converter prior to the final power amplifier to efficiently convert the linearly polarized Gaussian-shaped beam into a donut-shaped radially polarized beam. The desired vector beam was efficiently amplified yielding ∼110 ps pulses with a maximum output pulse energy of ∼30.7 µJ and a peak power of ∼280 kW at a repetition rate of 1.367 MHz. The average power was scaled up to 106 W by increasing the repetition rate to 5.468 MHz.