Microprocessing of a steel surface by single pulses of variable width

Single-pulse microprocessing of a steel surface with a variable pulse width (0.3-12.3 ps) and a wavelength of 515 nm was performed. The morphology of the craters was visualized by a scanning electron microscope and an optical profilometer. The nonmonotonic behavior of ablation thresholds with a minimum at ≈1.5 ps, due to achieving the electron-phonon relaxation time of the absorbed energy in the steel was revealed. It is shown that, with an increase in the pulse width in the considered width range, the efficiency of the ablation decreases by a factor of 2, which is explained by the partial transition from the phase explosion to the surface evaporation. © 2019 Astro Ltd.