315 mJ high-energy picosecond laser at 1 kHz repetition based on a zig-zag slab amplifier

We have demonstrated a 1 µm high-energy zig-zag slab laser amplifier. Operating at a repetition rate of 1 kHz, the output energy was 315 mJ with a pulse duration of 430 ps. A two-stage end-pumped Nd:YVO4 laser was used to pre-amplify the seed energy (320 µJ) of the passively Q-switched microchip laser to 6.2 mJ. After beam shaping, it enters the conduction cooled end-pumped slab (CCEPS) laser amplifier to produce hundreds of high-energy picosecond lasers. The gain effects of different seed energy injections and different zig-zag total reflection cycles were analyzed using the optimal beam-shaping device. The angles of incidence of 20.91° and 26.19° were chosen for the construction of the three-pass amplifier. Without the need for excessive gain crystals and beam control modules, this work boosts the pulse energy by three orders of magnitude. The peak power is 730 MW, and the conversion efficiency is 15%. To the best of our knowledge, this is the only report on the amplification of hundreds of picosecond lasers above three hundred millijoules at a repetition rate of 1 kHz using only a single CCEPS module. This high-energy laser will facilitate its application in industrial processing, biomedical and scientific research.