Coherent X-ray diffraction imaging of weak phase object by using a high aspect ratio aperture

Coherent X-ray diffraction imaging is one of the hottest research topics in advanced X-ray physics. The method reconstructs a real-space image from an oversampled diffraction signal by using computer algorithms instead of lenses. So far, its application has been limited to fairly strong phase objects, mainly due to parasitic scattering from the optics used for limiting the beam. Korean researchers recently published an interesting report on its application to a nonisolated weak phase object, a one-dimensional trench structure fabricated on a Si substrate. In their discussion, the authors reported that such work was enabled by employing a special aperture with a very high aspect ratio of nearly 100 made of tantalum (1.7 μm × 2.2 μm aperture with a thickness of 130 μm). For more information, see the paper, "Coherent hard x-ray diffractive imaging of nonisolated objects confined by an aperture", S. Kim et al., Phys. Rev. B81, 165437 (2010).