Hydrodynamic modeling and time-resolved imaging reflectometry of the ultrafast laser-induced ablation of a thin gold film

•A 150 nm thick thin film of gold deposited on 5 mm fused silica substrate, which was covered by an adhesion layer of about 20 nm chromium, was irradiated with single-pulsed ultrafast laser radiation in the gentle ablation regime (wavelength λ = 800 nm, pulse duration τH = 40 fs, peak fluence H0 = 1.4 J/cm2)•The resulting ablation structure features a flat topology with a constant ablation depth of approximately 70 nm in the center surrounded by a lamella-like structure with an irregular morphology•The optical response of the excited gold thin film was measured by ultrafast imaging reflectometry up to a delay time of 3.8 ns between the pump and the probe radiation (wavelength λ = 440 nm, pulse duration τH = 60 fs, angle of incidence θ=56∘)•The constant ablation depth is explained by quasi-two-dimensional two-temperature hydrodynamic modeling by the interference of two rarefaction waves•Excellent agreement between the simulated and experimentally determined topology of the ablation structure•The optical response reveals five stages of excitation, being completely explainable by modeling