Hard X-ray Holographic Microscope for 3D Phase Reconstruction of Semitransparent Object

Gabor和无透镜傅里叶变换全息显微镜已经被开发出来，用于(a)高分辨率相衬成像，(b)定量相位成像，(c)三维相位重建。SPring-8的x射线波动源与高分辨率带板的组合使我们能够制作小至100 nm尺寸的二次相干源。然后，在10kev的条件下，可以分辨出精细到100 nm的钽线和空间图案，同时也可以分辨出Gabor和无透镜傅立叶变换全息。这是在硬x射线全息摄影中报道的最高分辨率。无透镜傅里叶变换全息成像是边缘增强成像，因为全息图的中心区域必须被阻挡。为了实现定量相位成像，研制了一种双带板干涉仪的无透镜傅里叶变换全息显微镜。不仅可以重建钽图案的边缘图案，而且可以重建钽图案的内部平场。利用该光学系统，可以记录三维相位层析成像的投影数据，目前正在进行重建。光子工厂还研制了zernike型硬x射线相衬显微镜。在9kev下可以清晰地分辨出细至100 nm的钽线和空间图。为了制造小型x射线源，还研究了有限镜面的全反射。用8 keV的反射x射线照射金线的Gabor全息图证实了二次源尺寸的减小。这种方法可以用来制作一个小的全息参考源，其大小决定了空间分辨率。

Gabor and lens-less Fourier transform holographic microscopes have been developed for the purpose of (a) high-resolution phase-contrast imaging, (b) quantitative phase imaging, and (c) 3D phase reconstruction. A combination of the x-ray undulator source of SPring-8 and a high-resolution zone plate enabled us to make a secondary coherent source as small as 100 nm size. Then, a tantalum line and space pattern as fine as 100 nm could be resolved both Gabor and lens-less Fourier transform holography at 10 keV. This is the highest resolution that has been reported in hard x-ray holography. The image of the lens-less Fourier transform holography was edge-enhanced one because the central region of the hologram had to be blocked. For quantitative phase imaging, a lens-less Fourier transform holographic microscope with a double zone plate interferometer was newly developed. Not only the edge pattern but also the inside flat field of a tantalum pattern could be reconstructed. Using this optical system, projection data for 3D phase tomography could be recorded and the reconstruction is currently under way. A Zernike-type hard x-ray phase-contrast microscope was also developed at the Photon Factory. A tantalum line and space pattern as fine as 100 nm could be clearly resolved at 9 keV.To make a ID small x-ray source, total reflection from a limited mirror surface was also investigated. The reduction of the secondary source size was confirmed from the Gabor hologram of a gold wire illuminated with the reflected x-rays at 8 keV. This method can be used to make a small reference source of holography, the size of which determines the spatial resolution.