Methods for extending viewing-angle of holographic image by using digital hologram with high numerical aperture

Analysis on image recovery for digital Fresnel hologram with aliased fringe generated from self-similarity of point spread function

We analyze the aliasing phenomenon for digital Fresnel hologram with an enhanced numerical aperture (NA). The enhanced-NA digital hologram acquired computationally or optically at a closer distance from the object has an aliased fringe generated by undersampling process of the Fresnel prefactor. The point spread function known as Fresnel factor reveals a self-similar envelope when being sampled, which becomes a crucial mechanism in making this type of aliasing fringe of hologram. We describe that as the enhanced-NA hologram involves already the complementary aliased fringe that might come up i…

A wavelength and polarization selective photon sieve for holographic applications

Optical metasurfaces are perfect candidates for the phase and amplitude modulation of light, featuring an excellent basis for holographic applications. In this work, we present a dual amplitude holographic scheme based on the photon sieve principle, which is then combined with a phase hologram by utilizing the Pancharatnam-Berry phase. We demonstrate that two types of apertures, rectangular and square shapes in a gold film filled with silicon nanoantennas are sufficient to create two amplitude holograms at two different wavelengths in the visible, multiplexed with an additional phase-only holo…

用于扩展视场单次定量相位成像的编码孔径相关全息显微镜

Coded aperture correlation holographic microscope for single-shot quantitative phase imaging with extended field of view

本文提出在改进型马赫-曾德尔干涉仪中使用编码相位掩模，实现单次定量相位成像，并通过编码孔径框架扩展视场，性能优于开放孔径方法。

超窄线宽波长-涡旋超表面全息术

Ultranarrow-linewidth Wavelength-Vortex Metasurface Holography

本文提出超窄线宽波长-涡旋复用超表面全息术，结合色散工程与transformer神经网络，实现118个独立通道和2nm线宽，并应用于全息视觉密码学大幅提升安全性。

Suppressing meta-holographic artifacts by laser coherence tuning

A metasurface hologram combines fine spatial resolution and large viewing angles with a planar form factor and compact size. However, it suffers coherent artifacts originating from electromagnetic cross-talk between closely packed meta-atoms and fabrication defects of nanoscale features. Here, we introduce an efficient method to remove all artifacts by fine-tuning the spatial coherence of illumination. Our method is implemented with a degenerate cavity laser, which allows precise, continuous tuning of spatial coherence over a wide range with little variation in emission spectrum and total powe…

Gigapixel inline digital holographic microscopy using a consumer scanner

We demonstrate a gigapixel inline digital holographic microscopy using a consumer scanner. The consumer scanner can maximally scan an A4 size image (297mm x 210mm) with 4800 dpi (= 5.29 um), theoretically achieving a resolution of 56,144 x 39,698 = 2.22 gigapixels. The system using a consumer scanner has a simple structure, compared with synthetic aperture digital holography using a camera mounted on a two-dimensional moving stage. In this demonstration, we captured an inline hologram with 23,602 x 18,023 pixels (= 0.43 gigapixels). In addition, to accelerate the reconstruction time of the gig…

高数值孔径（NA）矢量全息图优化

High-NA vectorial hologram optimization

该研究提出基于梯度的纯矢量相位框架，采用可微理查兹-沃尔夫前向模型优化高NA计算机生成全息图，实现高均匀度强度轮廓，可优化偏振相关目标，残差显著降低。

Holographic Maxwellian near-eye display with adjustable and continuous eye-box replication

The Maxwellian display presents always-focused images to the viewer, alleviating the vergence-accommodation conflict (VAC) in near-eye displays (NEDs). However, the limited eyebox of the typical Maxwellian display prevents it from wider applications. We propose a holographic Maxwellian near-eye display with adjustable and continuous eye-box replication. Holographic display provides a way to match the human pupil size with the interval of the replicated eyeboxes, making it possible to eliminate or alleviate double image or blind area problem, which exists long in eyebox expansion for Maxwellian…

Resolution analysis in a lens-free on-chip digital holographic microscope

Lens-free on-chip digital holographic microscopy (LFOCDHM) is a modern imaging technique whereby the sample is placed directly onto or very close to the digital sensor, and illuminated by a partially coherent source located far above it. The scattered object wave interferes with the reference (unscattered) wave at the plane where a digital sensor is situated, producing a digital hologram that can be processed in several ways to extract and numerically reconstruct an in-focus image using the back propagation algorithm. Without requiring any lenses and other intermediate optical components, the …

通过双程数字微镜器件实现光学全息量子比特地址的10^{-5}水平相对强度串扰

Achieving $10^{-5}$ level relative intensity crosstalk in optical holographic qubit addressing via a double-pass digital micromirror device

本文提出利用双程数字微镜器件实现低串扰的全息量子比特地址方案，通过傅里叶平面全息和图像平面滤波技术，将串扰降至10^{-5}水平，适用于受困离子等量子系统。

Resolution enhancement by extrapolation of coherent diffraction images: A quantitative study on the limits and a numerical study of non-binary and phase objects

In coherent diffractive imaging (CDI) the resolution of the reconstructed object is limited by the numerical aperture of the experimental setup. We present here a theoretical and numerical study for achieving super-resolution by post-extrapolation of coherent diffraction images, such as diffraction patterns or holograms. We demonstrate that a diffraction pattern can unambiguously be extrapolated from only a fraction of the entire pattern and that the ratio of the extrapolated signal to the originally available signal is linearly proportional to the oversampling ratio. While there could be in p…

Large-scale Huygens metasurfaces for holographic 3D near-eye displays

Novel display technologies aim at providing the users with increasingly immersive experiences. In this regard, it is a long-sought dream to generate three-dimensional (3D) scenes with high resolution and continuous depth, which can be overlaid with the real world. Current attempts to do so, however, fail in providing either truly 3D information, or a large viewing area and angle, strongly limiting the user immersion. Here, we report a proof-of-concept solution for this problem, and realize a compact holographic 3D near-eye display with a large exit pupil of 10mm x 8.66mm. The 3D image is gener…