Laser–solid interaction in the femtosecond time regime

Modification of the surface structure of solid materials by laser radiation involves a complex chain of processes. The first step is the deposition of a certain amount of optical energy in the material. The character of the material excitation is strongly dependent on the laser pulse duration. With the use of ultrashort laser pulses non-equilibrium energy distributions with large excess population in the excited states can be produced. The distinct physical processes which come into play in laser–solid interaction on the ultrafast time scale open new routes of modifying the structure and the morphology of materials and offer interesting perspectives in laser materials processing.