high speed scanning versus beam division: technical and physical challenges for high power laser femtosecond processing.

The choice of the mean laser power for a fast fs laser process is strongly corelated with the beam engineering process strategy: whether the focus is on the pulses repetition rate (faster deflection of the beam with a high-speed scanner) or on the pulses energy (beam division) and how to distinguish between technical limitations of the tools used (scanner, diffractive optical elements) and physical limitations (thermal or non-thermal nature of physical mechanisms involved, and appearance of associated thermal effects depending on the parameters chosen for the process). High speed scanning ablation results on metallic and semiconductor materials will be compared with ablation performed by lines of spots, ranging from 1 to 50. A variation of the total fluence from 1 J/cm² up to 80 J/cm² is considered as well as several number of passes. The processing speed obtained will be compared with simulations to validate possible estimation of the processing time.