# A Versatile 100 Hz Laser System with Few-Cycle and TeraWatt Pulses for Applications
## 7 Conclusions  
We designed and implemented a laser system with two outputs, utilizing the recent achievements in Ti:Sa-based short pulse amplification and pulse compression. One branch of the system was capable of providing pulses with almost 2 TW peak power, while in the other branch, the bandwidth was broadened to support 2.5 cycle pulses. The three stage, 100 Hz repetition rate laser system is based on the configuration of negatively and positively chirped pulse amplification. This scheme maintains the bandwidth of the pulses under saturated amplification. This, complemented with three active beam pointing stabilization systems, ensures that the pulse energy of 50 mJ and duration of 26 fs were kept within 1% rms for several hours of daily operation. The repetition rate of the laser can be varied with a shutter prior to the power amplifier stage, while the repetition rate of the pump lasers was kept at 100 Hz. This solution maintains the thermal effects, so that the size of the output beam as well as the area of the focused beam change only a few percent upon varying the repetition rate of the laser between a few Hz and 100 Hz. In the few-cycle branch, the pulses from the first amplifier stage were temporally compressed with the combination of bulk and chirped mirrors. Such transform-limited, 28 fs pulses are spectrally broadened in a HCF. The temporally recompressed pulses exhibit a pulse duration of 7.1 fs and peak power of 35 GW, with an almost ideal Gaussian profile. Such a versatile laser system has been successfully used for the development of a high repetition rate target system, as well as a stationary target for a laser-generated neutron source. The system will be used for the generation of high spatial coherence X-ray radiation for computer tomography of 3D-printed objects. As the next step of laser development, we aim to combine the two branches. Here, the few-cycle pulses from the FE branch would be used for seeding the booster and power amplifiers. The amplification scheme would be altered for taking advantage of the broad bandwidth of polarization encoded chirped pulse amplification [41]. In this way, 12 fs laser pulses with 5 TW peak power are foreseen to be achieved, still at 100 Hz repetition rate. The initial design of the laser and the experiments were proposed by [PERSON], [PERSON], [PERSON], T.G., I.S. and A.K. built the FE, FCA, and TWA. The amplifiers were simulated by [PERSON] The dispersion management system was built and measured by [PERSON], [PERSON] and [PERSON]. The command-control system was implemented by [PERSON] and [PERSON]. The fs cutter was developed by [PERSON] and [PERSON]. The liquid jet was tested by [PERSON] and [PERSON]. The measurements with a conventional X-ray tube and simulations of laser-generated X-ray CT images were conducted by [PERSON] and [PERSON]. The implementation of the laser and the experiments were supervised by [PERSON] The original draft was prepared by [PERSON] from the contribution of all authors with their own section. The final editing, including graphs, was produced by [PERSON], while the final review by [PERSON] and [PERSON]. All authors have read and agreed to the published version of the manuscript. The project has been implemented with the support provided by the Ministry of Culture and Innovation of Hungary from the National Research, Development and Innovation Fund financed under NKFIH-877-2/2020, NKFIH-476-4/2021 and 2022-2.1.1-NL Creation of National Laboratories, Complex Development funding scheme. The raw data supporting the conclusions of this article will be made available by the authors upon request. The authors are grateful to [PERSON], [PERSON], and [PERSON] for their initial help in the preparation of the experiments, and to [PERSON] for providing the simulation code for laser amplification analysis. We also thank [PERSON] for carefully reading this manuscript.