X-ray Fourier transform holography with beam shaping optical elements.

Holography is a powerful method for achieving 3D images of objects. Extending this method to short wavelengths potentially offers significantly higher resolution than visible light holography. However, current X-ray holography setups employ nanoscale pinholes to form the reference wave. This approach is relatively inefficient and limited to very small sample size. Here, we propose a new setup for X-ray holography based on a binary diffractive optical element (DOE), which forms at the same time the object illumination and the reference wave. This optic is located separately from the sample plane, which permits investigation of larger sample areas. Using an extended test sample, we demonstrate a resolution of 90 nm (half-pitch) at an undulator beamline at BESSY II. The new holography setup can be directly transferred to free electron laser sources enabling time-resolved nanoscale imaging for ultra-fast processes.

Note: Thickness determination of freestanding ultra-thin foils using a table top laboratory extreme ultraviolet source.

We present a versatile and handy method allowing a thickness determination of freestanding thin plastic foils by its transmission characteristics in the extreme ultraviolet (EUV) spectrum. The method is based on a laser induced plasma source, emitting light in the EUV region, a compact double-mirror EUV monochromator operating at a fixed wavelength of 18.9 nm, and a CCD camera. The measurement delivers transmission values with a standard deviation of ΔT = 0.005 enabling foils thickness characterization with nm-accuracy at a given foil density and stoichiometric composition. Well characterized freestanding ultra-thin foils can be directly implemented in, e.g., high intensity laser matter experiments without further manipulation.