13-W picosecond Nd:GdVO4 regenerative amplifier with 200-kHz repetition rate

We report a diode-pumped picosecond Nd:GdVO4 regenerative amplifier system designed for micro-machining applications. Nd:GdVO4 was chosen as gain material because it offers – in comparison to the commonly used Nd:YVO4 – improved thermal properties and a larger gain bandwidth. At the maximum repetition rate of 200 kHz, the system generated 6.8-ps-long pulses with a pulse energy of 65 μJ, which corresponds to an average output power of 13 W. At 100 kHz, the pulse energy increased to 123 μJ, whereas the average power of 12.3 W remained almost identical. The broadening of the pulses due to gain narrowing was investigated in dependence on the number of cavity round trips and on the repetition rate. At 200 kHz, the injected 5.3-ps-long pulses broadened slightly to about 6.8 ps.