Diagnosing the evolution of laser-generated high energy density (HED) systems is fundamental to develop a correct understanding of the behavior of matter under extreme conditions. Talbot–Lau interferometry constitutes a promising tool, since it permits simultaneous single-shot X-ray radiography and phase-contrast imaging of dense plasmas. We present the results of an experiment at OMEGA EP that aims to probe the ablation front of a laser-irradiated foil using a Talbot–Lau X-ray interferometer. A polystyrene (CH) foil was irradiated by a laser of 133 J, 1 ns and probed with 8 keV laser-produced backlighter radiation from Cu foils driven by a short-pulse laser (153 J, 11 ps). The ablation front interferograms were processed in combination with a set of reference images obtained ex situ using phase-stepping. We managed to obtain attenuation and phase-shift images of a laser-irradiated foil for electron densities above ${10}^{22}\;{\mathrm{cm}}^{-3}$ . These results showcase the capabilities of Talbot–Lau X-ray diagnostic methods to diagnose HED laser-generated plasmas through high-resolution imaging.

在显微成像领域中，高成像质量图像的获取与良好的照明方式息息相关。传统显微镜使用聚光透镜来提供均匀强度的照明，调节聚光透镜的光阑匹配不同放大倍率的物镜。然而无色生物细胞的光学吸收系数低，在传统显微镜下难以观测到其细节信息。为了突破传统显微镜的成像功能，本文设计了一种可调控的显微镜聚光镜模块，通过将小型扭曲液晶器件嵌入聚光透镜的后焦面处，调控液晶器件的对光的透过效果可以实现明场成像以及差分相衬成像。系统由一款商用显微镜改装而成，液晶器件尺寸为22 mm×18 mm，实现了系统的高度集成化。通过实验验证了系统的成像性能，实现了对微凸透镜样品的定量相位重建，实验与理论曲线的互相关系数达到0.994 9，并且通过胚胎干细胞的重建展示了系统在实际应用中的效果。

The most recent discoveries in the biochemical field are highlighting the increasingly important role of lipid droplets (LDs) in several regulatory mechanisms in living cells. LDs are dynamic organelles and therefore their complete characterization in terms of number, size, spatial positioning and relative distribution in the cell volume can shed light on the roles played by LDs. Until now, fluorescence microscopy and transmission electron microscopy are assessed as the gold standard methods for identifying LDs due to their high sensitivity and specificity. However, such methods generally only provide 2D assays and partial measurements. Furthermore, both can be destructive and with low productivity, thus limiting analysis of large cell numbers in a sample. Here we demonstrate for the first time the capability of 3D visualization and the full LD characterization in high-throughput with a tomographic phase-contrast flow-cytometer, by using ovarian cancer cells and monocyte cell lines as models. A strategy for retrieving significant parameters on spatial correlations and LD 3D positioning inside each cell volume is reported. The information gathered by this new method could allow more in depth understanding and lead to new discoveries on how LDs are correlated to cellular functions.The most recent discoveries in the biochemical field are highlighting the increasingly important role of lipid droplets (LDs) in several regulatory mechanisms in living cells. LDs are dynamic organelles and therefore their complete characterization in terms of number, size, spatial positioning and relative distribution in the cell volume can shed light on the roles played by LDs. Until now, fluorescence microscopy and transmission electron microscopy are assessed as the gold standard methods for identifying LDs due to their high sensitivity and specificity. However, such methods generally only provide 2D assays and partial measurements. Furthermore, both can be destructive and with low productivity, thus limiting analysis of large cell numbers in a sample. Here we demonstrate for the first time the capability of 3D visualization and the full LD characterization in high-throughput with a tomographic phase-contrast flow-cytometer, by using ovarian cancer cells and monocyte cell lines as models. A strategy for retrieving significant parameters on spatial correlations and LD 3D positioning inside each cell volume is reported. The information gathered by this new method could allow more in depth understanding and lead to new discoveries on how LDs are correlated to cellular functions.

目前针对双相位光栅干涉仪灵敏度的分析存在着灵敏度模型不合理、理论结果不完整等问题，制约着系统灵敏度的提高。对此，提出了新的灵敏度模型，即物体所产生的条纹移动与光源位置变化产生的条纹移动是等效的。该灵敏度模型将物体对X射线的折射作用转化成了光源的移动，同时巧妙地利用了系统的劳条件将光源移动与成像条纹移动联系起来。利用新的灵敏度模型，成功获取了双相位光栅干涉仪和Talbot-Lau干涉仪的灵敏度，为优化系统灵敏度提供了理论指导。

Non-interferometric X-ray quantitative phase imaging (XQPI), much simpler than the interferometric scheme, has provided high-resolution and reliable phase-contrast images. We report on implementing the volumetric XQPI images using concurrent-bidirectional scanning of the orthogonal plane on the optical axis of the Foucault differential filter; we then extracted data in conjunction with the transport-intensity equation. The volumetric image of the laminate microstructure of the gills of a fish was successfully reconstructed to demonstrate our XQPI method. The method can perform 3D rendering without any rotational motion for laterally extended objects by manipulating incoherent X-rays using the pinhole array.

Applying an ultrafast vortex laser as the pump, optical parametric amplification can be used for spiral phase-contrast imaging with high gain, wide spatial bandwidth, and high imaging contrast. Our experiments show that this design has realized the 1064 nm spiral phase-contrast idler imaging of biological tissues (frog egg cells and onion epidermis) with a spatial resolution at several microns level and a superior imaging contrast to both the traditional bright- or dark-field imaging under a weak illumination of 7nW/cm2. This work provides a powerful way for biological tissue imaging in the second near-infrared region.

为了更好地理解相位光栅的成像过程，提出了一种新的分析方法——主级次分析法。主级次分析法分析相位光栅成像过程的关键思路在于找到相位光栅成像过程中起主要作用的衍射级次，忽略掉不重要的衍射级次，从而极大地化简了分析过程。主级次分析法的分析结果表明，对于占空比50%的π相位光栅，其在成像过程中起主要作用的是光栅的正负一级衍射，但正负三级衍射也是必不可少的。而对于占空比50%的π/2相位光栅，其成像过程中零级衍射的作用和正负一级衍射的作用同样重要，零级衍射不是仅仅产生有害的背景光强。

边缘增强作为一种图像处理技术，对于研究物体边界信息有着重要的应用。根据热光鬼成像的关联机制，将鬼成像与螺旋相衬成像技术相结合，把相位物体与涡旋滤光器非定域地放在热光鬼成像系统的探测光路和参考光路中，建立了相位物体边缘增强识别系统。实验结果表明，采用具有分数阶轨道角动量拓扑荷的涡旋滤波器可以实现轨道角动量值在0~1范围内的相位物体的边缘渐变性增强效果。随着轨道角动量拓扑荷数的增加，相位物体的边缘增强效果会越明显。非定域螺旋相衬成像相较于传统的螺旋相衬成像方案，突破了被测物体和涡旋滤波器在同一光路，并且滤波器必须放置在频谱面的空间局域性限制，解除了对主动照明光源相干性的要求，增强了涡旋滤波相衬成像系统的泛化能力。