Multipulse irradiation of silicon by femtosecond laser pulses: Variation of surface morphology

► Multipulse processing of Si by fs UV laser and evolution of surface structures. ► Multiscale structures range from nm to hundreds of micrometers. ► Generation of “carpet-like” pattern of spikes in the center of the spot. ► Evolution of a liquid foam layer on the silicon surface. ► Generation of surface tension waves at the peripheral region of the spot.