
Short wavelength radiation in the extreme ultraviolet (XUV) and soft X-ray spectral region enables high contrast and high-resolution imaging. WE utilize the highly coherent radiation of table-top high harmonic sources to perform lens-less imaging with wavelength-scale resolution down to only a few nanometers: The employed lens-less imaging methods are based on computational image formation by “digital optics”.
A record resolution of 13 nm has been achieved using coherent diffractive imaging on isolated samples [1]. Waveguiding effects in nanoscale structures have been observed with wavelength-scale resolution via Fourier-transform holography [2]. Recently, we achieved 45 nm resolution on an extended Siemens-Star test object by employing Ptychography, a scanning lens-less imaging technique [3], which enables quantitative imaging in amplitude and phase.
Our current research is focused on pushing resolution limits to the few-nm range [4], exploring broadband (potentially material-selective and ultrafast) lens-less imaging, and enabling imaging in the so-called water window for biological applications.
a) Simulation of the transmitted XUV light field behind a test sample. b) XUV image of the letter P obtained via Fourier-Transform-Holography (FTH). c) Helium-ion microscope image of the sample structure.
Picture: IAP (University Jena)