| Abstract [eng] |
Characteristics of negative dispersion coatings are studied in this thesis. Potentiality to control residual stress and increased laser induced damage threshold by material mixing and post deposition annealing in ion beam sputtered thin films is investigated. Finally, concept of flat focusing mirror based on negative dispersion mirror is presented. Clear interdependence between stress, annealing temperature and material mixing fraction is confirmed. Results are applied to design multi-layered structure with a completely compensated residual stress and thus precise flatness control. Also, before mentioned method was applied to so-called BASIC mirror to reach broadband negative dispersion characteristics while maintaining initial flatness of uncoated element. Mixtures in combination with annealing were also applied to make high reflection mirrors for 355 nm wavelength, thus reaching high LIDT values up to 14 J/cm2. It was demonstrated, that LIDT strongly depends on HfO2 fraction as well as on annealing temperature. It was also demonstrated, that in multilayer coatings, especially in negative dispersion coatings, LIDT depends on inner electric field distributions with respect to layer interfaces or high refractive index layers. LIDT increase by a factor of 2 was demonstrated by using special optimization procedure in negative dispersion coatings. Finally, flat focusing mirror, based on standard chirper mirror technology is demonstrated. |
