Fig. 1. (a) Schematic of SRRS process to achieve spectral broadening. (b) Evolution of energy depletion at different intensities of injected signal laser intensity for a pump laser intensity I = 2.2 GW/cm², a beam aperture L = 36 cm, and a propagation distance of 10 m in air. (c) Final depletion rate after 10 m propagation.

Fig. 2. (a) Comparison of near-field distribution with and without signal laser injection at the same energy depletion rate of 50%; (b) Time evolutions of the pump and Stokes lasers; the total temporal waveforms of the laser input and output remain the same.

Fig. 3. (a) Main optical system. (b) Schematic of final optical assembly: SHG, second-harmonic generation by KDP; THG, third-harmonic generation by DKDP; WFL, wedge focusing lens; VW, vacuum window; MDS, main debris shield, DDS, disposable debris shield.

Fig. 4. (a) Spectral distribution after SRRS process, with the pump laser at 350.55 nm. (b) Near-field distribution after SRRS with spectral bandwidth 1%, sampled by the BSG into the 3ω diagnostics system. (c) Temporal waveform of fundamental light (ω) and third harmonic (3ω) in the experiment.

Fig. 5. (a) Schematic of frequency conversion process. (b) Energy distribution of four components of the third harmonics after the frequency conversion process according to the harmonic converter program. (c) Final Stokes energy distribution after spectral broadening according to simulation and experiment. The experimental results are calculated by integrating the spectral data shown in Fig. 4(a), specifically by integrating the spectral intensity within ±0.18 nm of the center wavelength as the approximate energy share of that order.