title: UV spectral filtering by surface structured multilayer mirrors.
abstract: A surface structured extreme ultraviolet multilayer mirror was developed showing full band suppression of UV (λ=100-400  nm) and simultaneously a high reflectance of EUV light (λ=13.5  nm). The surface structure consists of Si pyramids, which are substantially transparent for EUV but reflective for UV light. The reflected UV is filtered out by blazed diffraction, interference, and absorption. A first demonstration pyramid structure was fabricated on a multilayer by using a straightforward deposition technique. It shows an average suppression of 14 times over the whole UV range and an EUV reflectance of 56.2% at 13.5 nm. This robust scheme can be used as a spectral purity solution for all XUV sources that emit longer wavelength radiation as well.
authors.forename: Qiushi
authors.initials: Q
authors.lastname: Huang
authors.forename: Daniel Mathijs
authors.initials: DM
authors.lastname: Paardekooper
authors.forename: Erwin
authors.initials: E
authors.lastname: Zoethout
authors.forename: V V
authors.initials: VV
authors.lastname: Medvedev
authors.forename: Robbert
authors.initials: R
authors.lastname: van de Kruijs
authors.forename: Jeroen
authors.initials: J
authors.lastname: Bosgra
authors.forename: Eric
authors.initials: E
authors.lastname: Louis
authors.forename: Fred
authors.initials: F
authors.lastname: Bijkerk