We are showing a significant enhancement in the temporal contrast by reducing the coherent noise of the 10 PW laser system at the Extreme Light Infrastructure - Nuclear Physics facility. The temporal contrast was improved by four orders of magnitude at 10 picoseconds and by more than one order of magnitude at 50 picoseconds before the main peak. This improvement of the picosecond contrast is critical for the experiments using thin solid targets.

Simultaneous ultra-intense pulses at petawatt laser facilities enable a broad range of experiments in nuclear photonics and strong field quantum electrodynamics. These experiments often require very precise control of the time delays between pulses. We report measurements of the time delay between the two 1 PW outputs of the Extreme Light Infrastructure - Nuclear Physics (ELI-NP) facility in Romania. The short-term standard deviation of the time delay was approximately half of the pulse duration of 23 fs, and the average delay drifted with up to 100 fs/h. The drift and sporadic delay jumps were corrected using a feedback loop, which reduced the long-term standard deviation of the delay close to its short-term value. These results imply that in ELI-NP experiments using two simultaneous pulses, a temporal overlap of better than half of the pulse duration can be achieved for more than two thirds of the shots, which would enable high data rate experiments using simultaneous petawatt pulses.

We demonstrate the sub-100 fs pulse generation from a dispersion-managed mode-locked Er:ZBLAN fiber laser at 2.8 μm. Both numerical simulation and experiment demonstrate that stretched-pulse and dissipative soliton mode lockings coexist in the near-zero-dispersion region of a fluoride fiber laser. With fine dispersion management, the shortest pulse of 95 fs was obtained from the stretched-pulse mode-locked Er:ZBLAN fiber laser, with an average power of 280 mW and repetition rate of 52 MHz. To the best of our knowledge, this is the shortest pulse to date directly generated from a mid-infrared mode-locked fluoride fiber laser.