Hard-X-Ray Lensless Imaging of Extended Objects

We demonstrate a hard-x-ray microscope that does not use a lens and is not limited to a small field of view or an object of finite size. The method does not suffer any of the physical constraints, convergence problems, or defocus ambiguities that often arise in conventional phase-retrieval diffractive imaging techniques. Calculation times are about a thousand times shorter than in current iterative algorithms. We need no a priori knowledge about the object, which can be a transmission function with both modulus and phase components. The technique has revolutionary implications for x-ray imaging of all classes of specimen.

Figure 1

Schematic of the experimental setup for a shifting specimen coherent x-ray diffraction microscopy.

Figure 2

Diagram of the phase-retrieval algorithm. The outer circular arrows indicate the position stepping within one iteration. The arrows within indicate (inverse) Fourier transforms and the desired input-output information.

Figure 3

Experimental results for a test sample with gold structures. (a) A scanning electron micrograph of the test sample with gold nanostructures. The circles indicate 18 of the 289 probe positions for which diffraction patterns were recorded. (b) Diffraction patterns for the positions indicated by white circles in (a). Subplots (c) and (d) are the reconstructed modulus and phase images displayed on a linear gray scale ranging from 0 to 1 and from $-\pi$ to $\pi$, respectively. The inset in (d) is a profile through the outermost rings of the zone plate which have a width of 100 nm. The moiré fringes visible in (d) are caused by the image compression necessary for reproduction but are not visible in the original full-size reconstruction.