Department of Chemistry, Brown University, Providence, Rhode Island 02912, USA.
Opt Lett. 2011 Jun 15;36(12):2209-11. doi: 10.1364/OL.36.002209.
Refractive index gradients in materials or at material interfaces lead to x-ray diffraction. Interference of this radiation with adjacent x-ray waves causes phase contrast that can be used for imaging purposes if an x-ray source with sufficient spatial coherence is used. The imaging modality presented here uses hard x radiation diffracted at interfaces, but requires only little spatial coherence. We report experiments showing, first, that image contrast is not diminished by motional blurring, and second, that contrast can be increased by orders of magnitude relative to in-line x-ray phase-contrast imaging. These properties substantially broaden the applicability of phase-sensitive imaging to moving samples and very weak density gradients.
物质或材料界面的折射率梯度会导致 X 射线衍射。如果使用具有足够空间相干性的 X 射线源，这种辐射会与相邻的 X 射线波相互干扰，从而产生相位对比，可用于成像目的。本文介绍的成像方式利用了界面处的硬 X 射线衍射，但只需要很少的空间相干性。我们报告的实验表明，首先，运动模糊不会降低图像对比度；其次，与线内 X 射线相位对比成像相比，对比度可以提高几个数量级。这些特性大大拓宽了相位敏感成像在运动样本和非常弱的密度梯度方面的应用。
