Fig. 1. Schematic of the optical path of the SG-II PW laser facility.

Fig. 2. Comparison of the signal-to-noise ratio of the front-end optical parametric chirped pulse amplification (OPCPA) output of the picosecond pulse before and after optimization.

Fig. 3. X-ray images and scanned intensity curve of the laser irradiating metal planar target: (a) image before optimization; (b) image after optimization; (c) scanned intensity curve along the x-direction.

Fig. 4. Light path and diagnostic arrangement of a laser-driven proton acceleration (LDPA) experiment based on the target normal sheath acceleration (TNSA) mechanism. (a) Schematic of the arrangement. (b) Photograph of the target chamber.

Fig. 5. Several images of different layers of radiochromic film (RCF) sheets showing proton signals with different proton energies.

Fig. 6. Two different double target structures. (a) Double-layer target for a plasma mirror. (b) Double-film target for sheath field modulation.

Fig. 7. Two-dimensional spatial distribution of electric field intensity for ps laser-driven single- and double-film targets. (a), (b) Single target and (c), (d) double-film target; (a), (c) at 500T₀ and (b), (d) at 700T₀.

Fig. 8. Several images of different layers of RCF sheets showing the proton beam output with higher cutoff energy using a double-film target.

Fig. 9. Maximum proton cutoff energy at different laser energies before and after maintenance.

Fig. 10. Electric field intensity distribution versus position for ps laser-driven single target and double-film target conditions. The data are from Figures 7(b) and 7(d). The blue line is for a single target and the red line is for a double-film target.