Flash Photoelectron Microscopy of Nano- and Femtosecond Laser-Pulsed Surfaces

摘要

A time resolving (5ns) photoelectron microscope was applied to visualize transient effects produced by 10 ns and 100 fs laser pulses in covalent material (Si) and metals (Co, Pt) below the ablation threshold on the thermal time scale above 10 ns. Pulses with ns duration caused thermal melting, removal of oxide from Si and oxidation of freezing Co. Femtosecond pulses converted an oxide-covered Si surface to a foam and left plastic deformations in metals. These deformations are probably caused by pressure from the excited electron gas and by shear due to constrained thermal expansion.