Fig. 1: Spatiotemporal reflectivity dynamics in air and water, recorded after subjecting the sample to pump pulses with a peak fluence of 1.5 ∙ Φ_thr.

Axis breaks at Δt = 21 ps were introduced in order to highlight the early reflectivity dynamics. a Color-coded relative reflectivity change ΔR/R₀ as a function of Δt and the distance from the irradiation center r for ablation in the air (top half) and water (bottom half). The initial reflectivity of Au in air and water is R₀ = 0.683 and R₀ = 0.636, respectively. ΔR/R₀ = 0.57 corresponds to 100% reflectivity of the Au surface in water. b ΔR/R₀ averaged over the region r ≤ 1.3 µm in (a) as a function of Δt in the air (black squares and lines) and water (blue circles and lines). The final state values ΔR_inf/R₀, recorded 5 s after pump-pulse impact are shown at the Δt labeled inf. Seven characteristic temporal domains are separated by red dashed lines and highlighted by red encircled numbers. Black arrows at Δt = 4 ns denote the delay time where the probe-pulse delay is switched from optically to electronically