Abstract

Laser ablation by nanosecond high power laser pulses is a topic of increasing interest in plasma physics and material processing technologies. It is applied as thin films deposition technique to a wide range of materials (e g. metals, semiconductors and superconductors). In particular, for metals the value of laser fluence required for significant vaporisation is nearly the same as the threshold value for plasma formation Thus in laser ablation of metals the plume results significantly ionised, and one of the characteristic features resides in the presence of ions with high kinetic energy in the flux of ablated particles. Moreover, the evaporation process is dependent on laser wavelength. Target irradiation by long wavelength (1-10 μm) causes a "thermal evaporation" process, whereas irradiation by short wavelength (e g. 193, 266, or 248 nm) often results in "non-thermal evaporation" processes. On the other hand, operating at intermediate wavelength region (e.g. 532, 355 or 351 nm) usually produces evaporation neither thermal nor photo-physical in nature.

© 1996 IEEE