Deterministic Shaping of Nanoplasma Shock Waves with Double-Pulse Femtosecond Laser Excitation

This work demonstrates deterministic control over the morphology of nanoplasma shock waves generated from isolated gold nanoparticles using temporally delayed dual-pulse femtosecond laser irradiation. By employing angle-resolved proton momentum imaging and multiscale numerical modeling that combines particle-in-cell simulations with a dissipative Gross–Pitaevskii equation framework, we reveal that the formation of highly structured shock waves—specifically, a distinctive triple-lobed pattern observed at a ~20 ps interpulse delay—stems from the resonant absorption of the second laser pulse by an expanding nanoplasma with a tailored density profile. Our findings indicate that the eventual profile of the shock wave is sensitive to the initial distribution of the involved particles at the arrival of the second laser pulse, with optimal coupling achieved when the plasma density nears the critical density. This ability to precisely shape nanoplasma shock waves opens promising avenues for applications in, e.g., compact laser-driven ion accelerators and targeted radiation-mediated therapies.