Thin disk amplifier-based 40 mJ, 1 kHz, picosecond laser at 515 nm

We report on a frequency-doubled picosecond Yb:YAG thin disk regenerative amplifier, developed as a pump laser for a kilohertz repetition rate OPCPA. At a repetition rate of 1 kHz, the compressed output of the regenerative amplifier has a pulse duration of 1.2 ps and pulse energy of 90 mJ with energy stability of σ < 0.8% and M² < 1.2. The pulses are frequency doubled in an LBO crystal yielding 42 mJ at 515 nm.