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We report on our efforts in design and construction of a compact Extreme Ultraviolet (EUV)-pump-probe microscope.
The goal is the observation of formation of nanostructures, induced by a femtosecond (fs)-laser pulse. The unique
interaction processes of fs-laser radiation with matter open up new markets in laser material processing and, therefore,
are actively investigated in the last decade. The resulting "sub 100 nm"-structures offer vast potential benefits in
photonics, biotechnology, tribological surface design, plasmonic applications and production of nanoparticles.
Focused fs-laser radiation causes a local modification resulting in nanostructures of high precision and reproducibility.
However the formation dynamics is not well understood. Research in this field requires high temporal and spatial
resolution. A combination of fs-laser and EUV-microscope provides a tool for "in situ"-observation of the formation
dynamics. As exemplary structures to be investigated, we use nanojets on thin gold films and periodic surface structures
(ripples) on dielectrics. In the future, the EUV-pump-probe microscope can become a versatile tool to observe physical
or biological processes.
Microscopy using EUV-light is capable of detecting structures on a scale down to several tens of nanometers. For
detailed investigations a compact EUV-microscope has been realized utilizing OVI Balmer-alpha radiation at 17.3 nm
coming from a discharge produced oxygen plasma. As optical elements a grazing incidence elliptical collector and a
zone plate with a width of outermost zone of 50 nm and a spectral filter to avoid chromatic aberrations are used. The
detector is a fast gated microchannel plate with a pore size of 2 microns contacted by a low impedance transmission line.
The expected spatial resolution of the setup is better than 100 nm and the time resolution is better than 1 ns. The newly
developed EUV-microscope is a powerful tool for a wide field of investigations that need high time and spatial
resolutions simultaneously.
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