Figure 1
From: Real-time and Sub-wavelength Ultrafast Coherent Diffraction Imaging in the Extreme Ultraviolet
The experimental setup for high resolution XUV imaging at high average power: (a), The pulses of a fiber based CPA (FCPA) system are spectrally broadened in a xenon filled hollow-core fiber and subsequently compressed with dielectric chirped mirrors (DCM). HHG is driven with 40 W of average power into a gas nozzle backed with 5 bar krypton. Two fused silica plates with antireflection coating for the IR are mainly reflecting the XUV light. Spectral selection of the 31st harmonic at 33.2 nm is done by a pair of aluminium filters followed by two curved XUV multilayer mirrors. The curved mirrors refocus the light tightly onto the sample. The diffracted light is captured by an XUV-sensitive CCD (CAM1). A beamstop (BS) suppresses the strong central speckle. (b) Measured XUV beam profile 20 mm behind the rear focus reveals good spatial beam properties. (c) The XUV multilayer mirrors, which are hit under almost normal incidence to minimize aberrations, have an overall reflectivity of 4.6% (solid black line) for the selected single harmonic line (dotted blue line).
