Development of Al- and Sc-based EUV multilayer mirrors

Evgueni Meltchakov (1) , Jennifer Rebellato (1) , Regina Soufli (2) , Sébastien de Rossi (1) , Franck Delmotte (1)

1 Laboratoire Charles Fabry / Optique XUV
2 LLNL - Lawrence Livermore National Laboratory

Here we report on recent advance in design, fabrication and characterisation of reflective multilayer coatings for scientific and technical applications in extreme- ultraviolet (EUV) spectral range. Development of EUV multilayer optics with specific spectral characteristics and enhanced temporal, thermal and radiation stability remains quite a challenge. Progress in this area is achieved by improving the technology of deposition of thin films, the evolution of methods for modeling and optimisation of multilayer structures, the use of modern possibilities of metrology, and, to a large extent, by searching for new materials and their combinations. We will present and discuss some results on periodic and aperiodic multilayer systems recently developed in LCF for various applications in an extended wavelength range (from 17 to 60 nm) - selective and large-band normal incidence mirrors using aluminum (Al) and scandium (Sc) [1-3]. The choice of these elements is due to their optical properties, in particular, a relatively low absorption coefficient in certain spectral regions. As an example of practical use, the first Sun images obtained with FSI (Full Sun Imager) and HRI (High-Resolution Imager) EUV telescopes of Solar Orbiter space mission, launched in 2020, for which the Al-based reflective coatings have been realised in our laboratory.

Domains: Physics [physics]

Evgueni Meltchakov, Jennifer Rebellato, Regina Soufli, Sébastien de Rossi, Franck Delmotte. Development of Al- and Sc-based EUV multilayer mirrors. Journée Couches Minces Optiques, COMET OOE du CNES; Société Française d'Optique, May 2022, Toulouse, France. ⟨hal-04550088⟩