Complex laser fields characterization at the dual arm 10PW laser system of ELI-NP

Following the commissioning of the dual arm 10 PW laser system (HPLS) of ELI-NP, extensive work on the laser system pulses qualification and tuning was performed. Here, there will be presented the progress achieved in several directions, including preliminary results of post-compression of 1 J, 26 fs pulses to less than 12 fs and focused helical beam. The in-house developed software routines for propagation of laser pulses with spatio-temporal couplings and for helical ultrashort pulses validated the measured effects. Qualification of the helical wavefront optical components was performed in order to distinguish between the helical plate imperfections and pulse quality distortions on the focal spot quality. Also, an electrical method to monitor damage threshold of the mirrors was proposed as laser healthcare monitoring method. Complementary, the relative temporal delay of the pulses on the parallel arms was measured and was stabilized at 11 fs at 1 PW output of the laser, after parallel propagation over 170m. Extension of the studies from 1 PW outputs to the 10 PW outputs will bring closer the realization of Compton back-scattering experiments in the strong field regime.