The viewing-angle enlargement of a holographic image is a crucial factor for realizing the holographic display. The numerical aperture (NA) of digital hologram other than a pixel specification has been known to determine the angular field extent of image. Here, we provide a valid foundation for the dependence of viewing angle on the hologram numerical aperture by investigating mathematically the internal structure of the sampled point spread function showing a self-similarity of its modulating curves. The enhanced-NA Fresnel hologram reconstructs the images at a viewing angle larger than a diffraction angle by a hologram pixel pitch where its angle value is expressed in terms of the NA of whole hologram aperture, which is systematically observed by optical hologram imaging. Finally, we found that the aliased replica noises generated in the enhanced-NA Fresnel diffraction regime are effectively suppressed within the diffraction scope by a digitized pixel. This characteristic enables us to overcome the image reduction and to remove the interference of high-order images, which leads to the wide viewing-angle holographic display. Optical experiments are shown to be consistent with the results of numerical simulation.
Swept-source optical coherence tomography by off-axis Fresnel transform digital holography with an output throughput of 10 Giga voxels per second in real-time
Gigapixel inline digital holographic microscopy using a consumer scanner
我们展示了一个千兆像素内联数字全息显微镜使用消费者扫描仪。消费型扫描仪最大可以扫描A4尺寸（297 mm x 210 mm）的图像，分辨率为4800 dpi（= 5.29 um），理论上达到56，144 x 39，698 = 2.22千兆像素。与使用安装在二维移动台上的相机的合成孔径数字全息术相比，使用消费者扫描仪的系统具有简单的结构。在这个演示中，我们捕获了一个23，602 x 18，023像素（= 0.43千兆像素）的内联全息图。另外，为了加快十亿像素全息图的再现速度，减少再现所需的存储量，我们将带限双步菲涅耳衍射应用到再现中。
Large-scale Huygens metasurfaces for holographic 3D near-eye displays
新的显示技术旨在为用户提供越来越身临其境的体验。在这方面，生成具有高分辨率和连续深度的三维（3D）场景是一个长期追求的梦想，该场景可以与现实世界叠加。然而，目前这样做的尝试未能提供真正的3D信息或大的观看区域和角度，从而严重限制了用户沉浸感。在这里，我们报告了这个问题的概念验证解决方案，并实现了具有10 mm x 8.66mm的大出瞳的紧凑型全息3D近眼显示器。3D图像是从具有大（>10^8）像素数和亚波长像素的高度透明的惠更斯超颖表面全息图生成的，该全息图通过深紫外浸没光刻法在300 mm玻璃晶片上制造。我们通过实验展示了高质量的虚拟3D场景，具有约50 k个活动数据点，连续深度范围从0.5米到2米，与真实世界重叠，易于肉眼观察。为此，我们引入了一种新的全息近眼显示器的设计方法，该方法本质上能够提供视差和调节提示，从根本上解决了当前商业3D显示器中存在的聚散度-调节冲突。
