Soft X-ray Vortex Beam detected by In-line Holography

Generation of electron vortex beams with over 1000 orbital angular momentum quanta using a tuneable electrostatic spiral phase plate

We report the use of an electrostatic MEMS-based device to produce high quality electron vortex beams with more than 1000 quanta of orbital angular momentum (OAM). Diffraction and off-axis electron holography experiments are used to show that the diameter of the vortex in the diffraction plane increases linearly with OAM, thereby allowing the angular momentum content of the vortex to be calibrated. The realization of electron vortex beams with even larger values of OAM is currently limited by the breakdown voltage of the device. Potential solutions to overcome this problem are discussed.

实验傅里叶变换X射线全息术中扩展和准备参考物的应用

Use of extended and prepared reference objects in experimental Fourier transform X-ray holography

使用一个或多个金纳米球作为参考对象的傅里叶变换全息术（FTH）进行了分析，使用实验软X射线衍射从这些球的分离集群组成的对象。全息图针对球参考对象进行去卷积以反转为图像，结合维纳滤波器以控制噪声。即使使用大的球簇作为参考，也可以获得小于一个球的~ 30 nm的分辨率，这是X射线FTH获得的最佳分辨率。讨论了由于光束光阑而引起的数据丢失的处理方法。提出了满足FTH条件的实际制备对象，并描述了形成它们的方法。

Generation of high-quality terahertz OAM mode based on soft-aperture difference frequency generation

We demonstrate the generation of high-quality tunable terahertz (THz) vortices in an eigenmode by employing soft-aperture difference frequency generation of a vortex output and a Gaussian mode. The generated THz vortex output exhibits a high-quality orbital angular momentum (OAM) mode with a topological charge of $\ell_{THz}=\pm1$ in a frequency range of 2-6 THz. The maximum average power of the THz vortex output obtained was ~3.3 $μ$W at 4 THz.

Maskless off-axis X-ray Holography

Off-axis X-ray holography is a lensless imaging technique that allows unambiguous retrieval of an object's exit-wave function with high fidelity. It has been used with great success to study nanoscale phenomena and spatio-temporal dynamics in solids, with sensitivity to the phase component of electronic and magnetic textures. However, the method requires patterning a nanostructured holography mask directly onto the sample. This invasive fabrication process is labor-intensive and defines a fixed field of view, limiting the range of applicable samples and diminishing the signal-to-noise ratio at…

采用均匀冗余阵列的超快、超亮X射线全息术

Ultrafast, ultrabright, X-ray holography using a uniformly-redundant array

自由电子激光的发展为在原子运动的时间尺度上研究电子世界提供了高分辨率成像的现实前景。我们确定X射线傅里叶变换全息术，（FTH）作为一个有前途的，但到目前为止，效率低下的计划做到这一点。我们发现，一个均匀冗余阵列（URA）放置在旁边的样品，乘以效率的X射线FTH超过一千（接近一个完美的镜头），并提供全息图像的振幅和相位对比度的信息。这里报道的实验证明了这一概念，通过成像的纳米制造的对象在同步辐射源，和细菌细胞在软X射线自由电子激光，其中照明由一个单一的15 fs脉冲成功地用于生产全息图像。我们预计即将推出的硬X射线激光器将实现更高的空间分辨率，并获得物质激发态的超快电影。

Vortex coronagraphy from self-engineered liquid crystal spin-orbit masks

We report on a soft route towards optical vortex coronagraphy based on self-engineered electrically tunable vortex masks based on liquid crystal topological defects. These results suggest that a nature-assisted technological approach to the fabrication of complex phase masks could be useful in optical imaging whenever optical phase singularities are at play.

全息术的射线光学方法

Ray Optics Approach to Holography

针对相位恢复中涡旋形成导致现有方法无法收敛的问题，提出基于最优传输的高效算法，规避相位涡旋并实现精度与效率的最优解，还揭示了其与射线光学极限的理论联系并在量子学习框架下重述问题，为相位恢复和激光束整形提供工具。

通过连续衍射光学操控软X射线束的轨道角动量

Manipulation of the orbital angular momentum of soft x-ray beams by consecutive diffractive optics

本研究通过连续衍射光学操控软X射线束的轨道角动量，实现了无需相敏技术的OAM测量，并应用于束流表征和散射实验。

YOSO：基于AI数据增强的单帧Gerchberg-Saxton相位恢复用于直射全息成像

YOSO: single-frame Gerchberg-Saxton phase retrieval with AI-based data augmentation for in-line holography

YOSO通过AI数据增强生成多高度数据集，结合传统Gerchberg-Saxton算法实现单帧全息成像的相位恢复，支持不同空间尺寸输入并具备物理一致的全息填充方法。