Comparative study of the ablation of materials by femtosecond and pico- ornanosecond laser pulses

A series of studies was carried out on the ablation of steel, Si3N4 ceramic , and diamond in air by femtosecond (200 and 900 fs) pulses of different wa velengths (532 and 266 nm) and in a wide energy density range (1-10(3) J cm (-2)). The ablation rates were measured for different geometries of the irr adiation surface [a shallow crater and a channel with a high (up to 10) asp ect ratio]. The ablation rates (in a shallow crater) and the morphologies o f the irradiated surface were compared for femtosecond and longer (220 ps, 7 ns) pulses. The role of the laser-generated plasma in the ablation of mat erials by subpicosecond pulses as well as the prospects for the practical a pplication of ultrashort laser pulses in the processing of materials are an alysed.