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.

In this contribution, we report about tomographic nanoscale imaging using a laser-produced plasma-based laboratory transmission X-ray microscope (LTXMLTXM ) in the water window. The soft X-ray radiation of the LTXMLTXM is provided by a high average power laser-produced (1.3 kHz repetition rate, 0.5 ns pulse duration, 140 W average power) plasma source, a multilayer condenser mirror, an objective zone plate, and a back-illuminated CCD camera as a detector. In the second part of the contribution, we will present recent results on holography and coherent diffraction imaging using our high repetition rate X-ray laser. We will discuss advantages of these methods and its potential for nanoscale imaging.

Nanoscale imaging of biological samples in the lab as well as mask inspection in extreme ultraviolet lithography near the production line with sub 30 nm resolution require high spectral brightness soft x-ray sources. Laser produced plasma (LPP) sources and plasma based X-ray lasers (XRL) emit soft X-ray radiation in the wavelength region of interest between 2 and 20 nm. Whereas LPP sources easily can be tuned to the so called water window (2.2–4.4 nm) the output of an XRL is restricted to relatively few fixed wavelengths in the extreme ultraviolet range. However due to the relatively high degree of coherence the XRL is well suited also for nanoscale imaging using coherent techniques like coherent diffraction imaging or Fourier transform holography.

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.