Hard x-ray scanning microscopy with coherent radiation: Beyond the resolution of conventional x-ray microscopes

Abstract

We demonstrate x-ray scanning coherent diffraction microscopy (ptychography) with 10 nm spatial resolution, clearly exceeding the resolution limits of conventional hard x-ray microscopy. The spatial resolution in a ptychogram is shown to depend on the shape (structure factor) of a feature and can vary for different features in the object. In addition, the resolution and contrast are shown to increase with increasing coherent fluence. For an optimal ptychographic x-ray microscope, this implies a source with highest possible brilliance and an x-ray optic with a large numerical aperture to generate the optimal probe beam.

Coherent X-ray diffractive imaging on the single-cell-level of microbial samples

“…correcting for positional errors [20,110,182,307] but on the experimental side this problem is currently mainly approached by increasing the uence, e.g. [111,133,266,286,287,332].…”

“…Especially, in the eld of X-ray microscopy, ptychography has advanced to a powerful tool for imaging on the scale of a few nanometres of arti cial test structures in 2d [266,287,330,332] and 3d [59,133] as well as, for instance, biological specimen in 2d [62,97,172] and 3d [61,109,330]. Moreover, the ptychographic method has also been used for elemental speciation [21,135,285] and for sequential imaging of chemical reactions [142].…”

“…First results using divergent beams have been reported, including nanofocusing refractive X-ray lenses [134,265,266], Fresnel zone plates [143,312,330] and Kirkpatrick-Baez (KB) mirrors [98,143,286,287]. KB mirrors are attractive focusing devices due to their high e ciency at sub 100 nm focusing while providing long working distances of hundreds of millimetres [130, 189, 199 201].…”

“…In principle, the capability to separate the illuminating wave-eld from the object makes the retrieved object information free of aberrations. If the experimental conditions are su ciently good ptychography has even proven to yield quantitative phase maps with a resolution of the object information below 10 nm in two dimensions [266,287] and around 16 nm in three dimensions [133]. Recently, ptychography could also be shown to yield information under non-ideal experimental conditions such as a low degree of spatial and temporal coherence of the illuminating wave-eld [78,299] but also vibrational modes of the object could be extracted [42].…”

“…That is, the obtained resolution is increasing but it remains well above the wavelength (cf. [133,266,314]). …”