Fig. 1. Diffraction transmission schematic of beam after passing through a single lens. (a) Schematic of diffraction transmission; (b) schematic of lens structure

Fig. 2. Schematic of broadband laser pulse transformation by a lens. (a) Without considering GVD; (b) considering GVD

Fig. 3. Schematic of beam radius selection

Fig. 4. Layout diagram of high-energy Nd:glass petawatt laser facility with multi-pass amplification structure

Fig. 5. Influence of different PTD/T on focal spot distribution. (a), (b), (c), and (d) are 3D distributions of spatiotemporal characteristics of focal spot at PTD/T = 0, 1, 3, and 5, respectively; (e), (f), (g), and (h) are iso-intensity curves of focal spot at PTD/T = 0, 1, 3, and 5, respectively

Fig. 6. Variations of focal spot characteristics with different PTDs. (a) Far-field pulse shape; (b) relative intensities of spatial focal spots; (c) energy concentrations of focal spots

Fig. 7. Spatiotemporal characteristics of focal spot under different compression pulse widths with injecting laser of 3.2 nm broadband and ideal beam quality of 1 DL, and when PTD is 2.5 ps. (a) T=0.5 ps; (b) T=1 ps; (c) T=5 ps; (d) T=10 ps

Fig. 8. Focal spot characteristics under different compression pulse widths. (a) Spectrum distribution of focal point; (b) spatial waveform of focal spot; (c) temporal waveform of focal spot

Fig. 9. Influence of PTD on focal spot under different injected beam qualities. (a), (b), (c), and (d) are spatiotemporal characteristics of focal spot when beam qualities are 1 DL, 3 DL, 5 DL, and 7 DL, respectively; (e) comparison of temporal waveform after spatial integration