Suppression of nanosecond pre-pulses from regenerative amplifier and multi-pass amplifiers in the SULF-1PW laser

In this research, we report the latest progress on the suppression of nanosecond pre-pulses from regenerative amplifier and multi-pass amplifiers in the SULF-1PW laser. The pre-pulse generated from the Pockels cell in regenerative amplifier (RA) is delay shifted by enlarging the distance between the Pockels cell and the nearby cavity mirror, and then removed by the extra pulse pickers outside the RA. The pre-pulses arising from multi-pass amplifiers are also further suppressed by adopting a novel amplifier configuration and properly rotating the Ti:sapphire crystals. After the optimizations, the temporal contrast on nanosecond time scale is promoted to be better than a contrast level of 10-9. This research can provide beneficial guidance on the suppression of nanosecond pre-pulses in the high-peak-power femtosecond laser systems.