Chinese Optics Letters, Volume. 23, Issue 11, (2025)
Transient Recovery Window: Bridging Plasma Recombination and Shockwave Genesis [Early Posting]
Plasma shielding is a critical limiting factor in enhancing the quality and efficiency of femtosecond laser processing. This study investigates the temporal evolution of femtosecond laser-induced plasma in water, unveiling a transient recovery window occurring between plasma recombination completion and shockwave generation. During this window, the plasma density returns to baseline levels and exerts negligible influence on probe light transmission. Furthermore, the plasma recombination time exhibited a strong dependence on the pump pulse energy. The pump pulse energy densities of 2.15, 2.77, and 3.72 J/cm² correspond to plasma recombination times of 231.0, 125.4, and 112.2 ps, respectively. This advancement could potentially offer a valuable reference for optimizing pulse sequences in high-repetition-rate processing.