Abstract
Nowadays, ultrashort pulse laser developing laboratories have an increasing demand for optical interference coatings, mostly for dielectric high reflectors (HR-s) with prescribed phase properties. There are two major reasons for this: on the one hand, conventional dielectric HR-s do not meet the expectations of laser developers due to the enormous bandwidth of the existing femtosecond (1 fs = 10-15 s) pulse laser systems. On the other hand, by the development and application of HR-s with special phase characteristics more compact laser systems with higher performance can be built, which can significantly lower the production costs and thus allow for mass application. Different applications call for different femtosecond pulse laser systems with individually designed thin film optics. In order to achieve the best compromise between the thin film requirements and the technological possibilities, a deep knowledge of such lasers is essential.