Acoustically-driven femtosecond laser ablation of atomically thin molybdenum disulfide

Femtosecond (fs) time-resolved microscopy is employed to investigate the dynamics of transient Newton rings generated during fs-laser ablation of nanometer-thin films of MoS₂, AuPd and hybrid AuPd/MoS₂ bilayers. By systematically varying the film thickness L, a thickness-independent ablation behavior is revealed, characterized by a constant absorbed energy density at the ablation threshold. Expansion velocities of the ablating films are extracted from the temporal evolution of the Newton ring fringes. These velocities are largely independent of film thickness, consistent with a thermoelastic model explaining the acoustic delamination at the film-substrate interface. This study provides quantitative insight into ultrafast thin film ablation mechanisms and outlines new approaches for engineering transient 2D material architectures with potential applications in nanophotonics and ultrafast quantum optics.