High efficiency laser-driven proton sources using 3D-printed micro-structure
Chengyu Qin, H. Zhang, Shun Li, Nengwen Wang, Angxiao Li, Lulin Fan, Xiaoming Lu, Jinfeng Li, Rongjie Xu, Cheng Wang, Xiaoyan Liang, Yuxin Leng, Baifei Shen, Liangliang Ji, Ruxin Li
Abstract
Abstract Fine structured targets are promising in enhancing laser-driven proton acceleration for various applications. Here, we apply 3D-printed microwire-array (MWA) structure to boost the energy conversion efficiency from laser to proton beam. Under irradiation of high contrast femtosecond laser pulse, the MWA target generates over 1.2 × 10 12 protons (>1 MeV) with cut-off energies extending to 25 MeV, corresponding to top-end of 8.7% energy conversion efficiency. When comparing to flat foils the efficiency is enhanced by three times, while the cut-off energy is increased by 32%. We find the dependence of proton energy/conversion-efficiency on the spacing of the MWA. The experimental trend is well reproduced by hydrodynamic and Particle-In-Cell simulations, which reveal the modulation of pre-plasma profile induced by laser diffraction within the fine structures. Our work validates the use of 3D-printed micro-structures to produce high efficiency laser-driven particle sources and pointed out the effect in optimizing the experimental conditions.