Since the Eighties a new type of laser appeared: the femtosecond laser. It is not the wavelength or the active medium used which characterizes this laser and which gives him its name, as for the other types of laser (YAG, CO2, Excimère…) but its original operating mode. This type of laser is able to provide pulse duration going from picosecond (1 ps = 10-12 s) to a few ten femtosecond (1 fs = 10-15 s). The term of ultra short pulses is also used. Only laser technologies can reach such short durations, inaccessible to the electronic technology ones. The use in laboratory [1] of such ultra short pulses made it possible to also show the completely original character of the laser matter interaction in femtosecond mode, which thus leads to specific results during the use of this laser radiation on materials.

[1] The Hubert Curien laboratory (CNRS UMR 5516) of the University Jean Monnet (Saint-Etienne) has developed for more than ten years themes of research aiming at the comprehension of the mechanisms of the interaction between ultra short pulses and metals or transparent materials. The research team of the Hubert Curien laboratory, precursor in France of the developments of research in the field of ultra fast processing, has a strong national and international impact (students post American Doc., Co supervision thesis with German universities, projects ANR of great scale). The Hubert Curien Laboratory and the company IMPULSION have signed since 2003 a contract of collaboration.