Influence of an external pressure and of the type of gas on the mechanism and rate of breakdown of metals by Nd:YAG laser pulses

A study was made of the interaction of high-power laser radiation with metal (W, Fe, Tl, stainless steel) surfaces at high external pressures of inert (Ar) and active (O₂) gases. A study was made of the rate of breakdown of stainless steel samples when the power density of the laser pulses was 0.5 — 10 MW cm^–2 and the external pressures ranged from 0.1 Torr to 15 bar. Considerable differences were observed between the rates of breakdown in gases of different nature. A study was made of the dynamics of changes in the profiles of high-power laser pulses reflected from the surfaces of W, Fe, and Ti.