Narrowband multilayer coatings for the extreme ultraviolet range of 50-92 nm

Manuela Vidal-Dasilva, Mónica Fernández-Perea, José A. Méndez, José A. Aznárez, and Juan I. Larruquert


A new type of multilayer coatings with narrowband reflection properties and peaked in the ~50– 92 nm spectral range has been developed. Multilayers are based on Yb, Al, and SiO films and they have been prepared by thermal evaporation. Efficient multilayers based on Yb and Al, with an SiO protective layer were prepared, but they developed a dendrite structure, which was attributed to the reactivity between Al and Yb. Multilayers based on Yb and Al, with both SiO protective and barrier layers, resulted in efficient reflective filters, with no observable dendrite growth. The peak reflectance of aged multilayers was of the order of ~0.20, with bandwidths in the range of 12 to 22 nm FWHM.