We report the delivery of 3 PW on-target peak power laser pulses using the SILEX-II petawatt laser facility, which is fully based on optical parametric chirped-pulse amplification. To achieve this goal, efforts have been made to improve the stability of the compressed pulse and to scale up the energy of the main amplifier. Active pump-seed pulse synchronization of the ps-OPCPA frontend has been adopted to reduce the timing jitter between the pump and signal from over 1ps to below 100fs, ensuring stable amplified spectra. A stable and nearly Fourier transform-limited pulse with a duration of approximately 21 fs has been achieved through the use of active pump-seed pulse synchronization. The main amplifier has been optimized to a two-stage OPCPA compared to its original one-stage configuration. A maximum output energy of 131.4J has been achieved with the two-stage OPCPA, and the corresponding on-target energy is 72.3J, taking into account the transmission efficiency from the compressor to the target. More than 15 shots with an energy exceeding 60 J at the target have been delivered in our recent experiments, demonstrating the capability of our laser system to achieve 3 PW on-target peak power.

petawatt laser facility,optical parametric chirped pulse amplification,peak power