Ultra-short pulse lasers: applications

Ultra-short laser pulses are a new laser technology providing access to a highly original mode of laser-matter interaction compared with the interaction mechanisms underlying conventional laser processes. Ultra-short laser pulses cover a range of pulse durations from femtoseconds (10 ^–15 s) to picoseconds (10 ^–12 s). These pulses can be the source of innovative technologies, but it's important to understand their specific features in order to use them wisely. This article does not deal with the field of high laser energies (that of large instruments such as the Laser Megajoule, LMJ), where femtosecond technologies also play a role. Instead, we'll be looking at energies associated with actual or potential industrial applications of ultrashort pulses. The article [AF 3 282] presents the operating principles of femtosecond lasers in detail, so we'll be focusing more on the characteristics of laser-matter interaction in ultra-short mode to grasp all the consequences.

The laser process itself must be mastered before moving on to the industrialization stage. This is already true for all laser applications, and even more so for ultrafast applications. Which begs the question: when will this technology make it out of the laboratory? Femtosecond lasers are widely used in various fields of research, and are associated with an abundant scientific output. Physical phenomena can be "seen" on a time scale otherwise inaccessible. Very early on, it was possible to imagine that this specificity could also lead to applications in the industrial sector, innovative applications capable of producing achievements that were hitherto technically impossible. But is such a technology capable of reaching the industrial stage? In France, several technical centers have been resolutely pursuing this path since the 2000s, against a backdrop of strong competition, mainly from Germany and Japan. Thanks to the very early development in France of laser sources adapted to industrial applications, these technologies have now reached the level of maturity required to reach the industrial stage: a production machine in the mechanical engineering field, for example, was installed in Saint-Étienne in 2009 (see figure 21...