A colliding microjet liquid sheet target system was developed and tested for pairs of round nozzles of 10, 11 and 18 μm in diameter. The sheet’s position stability was found to be better than a few micrometers. Upon interaction with 50 mJ laser pulses, the 18 μm jet has a resonance amplitude of 16 μm at a repetition rate of 33 Hz, while towards 100 Hz it converges to 10 μm for all nozzles. A white-light interferometric system was developed to measure the liquid sheet thickness in the target chamber both in air and in vacuum, with a measurement range of 182 nm–1 μm and an accuracy of ±3%. The overall shape and 3D shape of the sheet follow the Hasson–Peck model in air. In vacuum versus air, the sheet gradually loses 10% of its thickness, so the thinnest sheet achieved was below 200 nm at a vacuum level of 10^–4 mbar, and remained stable for several hours of operation.

We developed a versatile 100 Hz laser system based on negatively and positively chirped pulse amplification. The few-cycle output provides pulses with 7.1 fs and 0.25 mJ, while the power output supports 26 fs pulses with 50 mJ. The energy as well as the pulse duration stability of the system are below 1%, while the pointing stability is within 25% of the diffraction-limited spot size. We also show applications in high repetition rate target development and preparation for a laser-generated X-ray source for industrial CT imaging.

Compared to their conventional counterpart, laser plasma-based ion accelerators offer considerably higher acceleration gradients, opening the way to more compact laser-driven accelerator facilities. In this context, deuteron acceleration has been used for laser-based neutron sources, as deuterons at relatively low kinetic energy can efficiently generate neutrons. While double-pulse and chirp effects have been explored for proton acceleration under radiation pressure and target-normal sheath acceleration schemes, their role in ion acceleration remains unconfirmed, limiting the optimization strategies for neutron sources. Here we clarify the influence of laser pulse temporal shape on ion acceleration from ultrathin targets. We systematically change the temporal structure of the pulse by controlling the group delay dispersion and third-order dispersion (TOD), while pulse energy and focal spot size remain unchanged. The experiments are supported by 2D PIC simulations and analytical modeling. We find that the effect of optimum temporal shape is considerably larger than previously reported: the TOD-induced post-pulses increase the efficiency by 50% and double the deuteron cutoff energy. Our systematic study shows that the performance of laser ion accelerators can be strongly enhanced by matching the dispersion values to the target characteristics.

We developed a versatile 100 Hz laser system based on negatively and positively chirped pulse amplification. The few-cycle output provides pulses with 7.1 fs and 0.25 mJ, while the power output supports 26 fs pulses with 50 mJ. The energy as well as the pulse duration stability of the system is below 1%, while the pointing stability is within 25% of the diffraction limited spot size. We also show applications in high repetition rate target development and preparation for a laser-generated X-ray source for industrial CT imaging.