Ptychographic coherent diffractive imaging of weakly scattering specimens

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

“…A comparison of the 2d power spectral densities (PSD) of the reconstructed phase maps (cf. [62,97]. The resolution of the object cannot be better than 38 nm as the PSD analysis revealed.…”

“…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].…”

“…In this experiment, a set of j = 1, ..., J di raction patterns was collected by scanning the sample along concentric circles in a XY −plane (cf. [62], Fig. 3.33(a)) allowing adjacent illuminated spots to overlap (in uence of the overlap parameter see [30]).…”

“…Here, two di erent ptychographic algorithms were used:`DM' (di erence-map) [294] (and references therein) and`ePIE' [183] (see also section 1.3.6, p. 40). Following the strategy of [62], a Siemens star resolution test chart (model ATN/ XRESO-50HC, NTT-AT, Japan) was used in order to get a good estimate of the probe, which could be used as an initial guess for the phasing of the bacterial specimens.…”

Lensless X-ray imaging in reflection geometry

“…2 Lensless x-ray imaging techniques such as coherent diffraction imaging (CDI) 1-8 and ptychography [9][10][11] , and Fourier transform holography (FTH) [12][13][14][15][16][17] can provide time-resolved, diffraction-limited images. Nearly all examples of these techniques have been focused on transmission geometry, restricting the samples and reciprocal spaces which can be investigated.…”