Study of the Parameters of Laser-Induced Shock Waves for Laser Shock Peening of Silicon

Abstract

The ranges of energies of femtosecond laser pulses and distances from the focusing point of intense (up to 1013 W/cm2) femtosecond laser radiation to a silicon sample in which phase transitions can be initiated have been determined using the time-resolved shadow photography technique. It has been found that the tight focusing (NA = 0.5) of femtosecond near infrared laser radiation provides a pressure of 15 GPa, which corresponds to a pressure of (40 ± 6) GPa in the case of laser shock peening of silicon and exceeds the threshold value necessary for the initiation of a family of phase transitions (11, 14, and 33 GPa). The pressure on the front of the shock wave propagating in the medium decreases rapidly (in 2.5 ns) below this threshold value, which significantly restricts the possible application regimes of laser shock peening.