Fig. 1. SG-II-UP picosecond petawatt laser. (a) Left beamline of SG-II-UP is picosecond petawatt laser; (b) schematic diagram of a picosecond petawatt laser; (c) large-aperture pulse compression grating

Fig. 2. Main source of time domain noise of a petawatt laser pulse

Fig. 3. Improvement of SNR for laser seed source in SG-II-UP PW. (a) Schematic of ps-OPA^[62]; (b) measurement results of SNR enhancement

Fig. 4. Pre-pulses and stray light sources of a multi-pass amplifier. (a) Schematic of a multi-pass amplifier; (b) two types of pencil beam

Fig. 5. SNR measurement results of a multi-pass amplifier. (a) Pre-pulses in time range when PEPC is on; (b) pre-pulses outside time range when PEPC is on

Fig. 6. Main wave aberrations affecting focusing ability of a picosecond petawatt laser

Fig. 7. Wavefront control of NIF^{[48, 110]}. (a) Control standards for large aperture optics; (b) pump induced thermal distortion of Nd∶glass; (c) deformable mirror; (d) typical focal spots of NIF-ARC

Fig. 8. Wavefront control of OMEGA-EP^[113-116]. (a) Optical path schematic diagram of OMEGA-EP device with dual deformable mirrors; (b) typical focal spot

Fig. 9. Improvement of wavefront measurement in PHELIX^[108,117]. (a) A new scheme of wavefront measurement; (b) distribution of focal spots before wavefront measurement improvement; (c) distribution of focal spots after wavefront measurement improvement

Fig. 10. Focusing ability of SG-II-UP PW laser. (a) Residual wavefront error: PV of 0.57λ, RMS of 0.11λ; (b) focal spot measured by X-ray pinhole camera [FWHM 17.0 μm(H)×20.8 μm(V)]; (c) measurement results of far-field focal spot; (d) encircled energy analysis of focal spot distribution in (c)

Fig. 11. High fidelity focal spot measurement technology^[118-123]. (a)(b) Indirect measurement technology of focal spot and algorithm in OMEGA-EP based on phase recovery algorithm; (c) an in-situ focal-spot microscope used in OMEGA-EP; (d) diagram of indirect measurement technology of focal spot based on coherent modulation imaging in SG-II-UP PW; (e)(f) comparison of indirect and direct measurements of focal spot in SG-II-UP PW

Fig. 12. Laser pulse distribution with different STCs^[108]. (a) Laser pulse with PFT; (b) laser pulse with PFC; (c)(d) spatial phase distribution for three different frequencies ω₁ <ω₀ <ω₂ of pulse for (a) and (b), respectively

Fig. 13. Schematic of pre-compensation techniques for the radial group delay^{[115, 127-130]}

Fig. 14. Application of an focused plasma mirror based on ellipsoid^[131]. (a) Experimental diagram; (b) focal spot distribution in traditional off-axis parabolic mirror focusing system; (c) distribution of focal spot under ellipsoidal focusing plasma mirror

Fig. 15. Output capability analysis of SG-II-UP PW. (a)(b) Output capability of a multi-pass amplifier; (c) near field distribution of main amplifier; (d) near field distribution after pulse compression

Fig. 16. Online damage measurement technology for large-aperture grating. (a) Schematic of dark-field scattering imaging; (b) damage measurement result of a grating G4

Fig. 17. Technology of active laser-pointing stabilization^[146]. (a) Schematic of active laser-pointing stabilization control system in SG-II-UP PW system; (b) measurement result of the laser pointing stability in open-loop and in closed-loop

Fig. 18. Schematic overview of hundred terawatt undulator (HTU) experimental setup with active control system of laser pointing^[148]

Fig. 19. Schematic of optomechanical coupling active control for spatial filter system of a PW laser^[149]

Fig. 20. Scheme of synchronization measurement for nanosecond laser pulses. (a) Synchronization measurement schematic diagram of NIF time^[156]; (b) synchronization measurement schematic diagram of OMEGA^[157]

Fig. 21. Synchronization measurement of LMJ-PETAL^[160]. (a) Schematic diagram of 2D-SI; (b)(c) images of fringes for a delay of 50 fs and for a delay of 3 ps respectively

Fig. 22. Schematic and core technologies of a high-energy high-repetition-rate picosecond-petawatt laser^[168-172]

Fig. 23. Pulse amplification and compression technology in a plasma. (a) Joule level sc-SBS plasma amplification results^[180];

Fig. 24. Enabling technology for picosecond petawatt laser. (a) Post pulse compression technology^[12]; (b) Nexawatt concept^[10]