Infrared diffractive filtering for extreme ultraviolet multilayer Bragg reflectors.
We report on the development of a hybrid mirror realized by integrating an EUV-reflecting multilayer coating with a lamellar grating substrate. This hybrid mirror acts as an efficient Bragg reflector for extreme ultraviolet (EUV) radiation at a given wavelength while simultaneously providing spectral-selective suppression of the specular reflectance for unwanted longer-wavelength radiation due to the grating phase-shift resonance. The test structures, designed to suppress infrared (IR) radiation, were fabricated by masked deposition of a Si grating substrate followed by coating of the grating with a Mo/Si multilayer. To give the proof of principle, we developed such a hybrid mirror for the specific case of reflecting 13.5 nm radiation while suppressing 10 μm light, resulting in 61% reflectance at the wavelength of 13.5 nm together with the 70 × suppression rate of the specular reflection at the wavelength of 10 μm, but the considered filtering principle can be used for a variety of applications that are based on utilization of broadband radiation sources.
FOM Institute DIFFER – Dutch Institute for Fundamental Energy Research, PO Box 1207, 3430 BE Nieuwegein, The Netherlands. V.V.Medvedev@differ.nl
V V
VV
Medvedev
A J R
AJ
van den Boogaard
R
R
van der Meer
A E
AE
Yakshin
E
E
Louis
V M
VM
Krivtsun
F
F
Bijkerk
D004867:Equipment Design; D019544:Equipment Failure Analysis; D007259:Infrared Rays; D007909:Lenses; D012031:Refractometry / Q000295:instrumentation*