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Phase flicker can degrade the performance of holographic applications at the device and application levels. On the device side, the meaningful phase modulation resolution is proved to be limited by the overlapping between adjacent phase levels caused by flicker. Here, the tolerance of the overlapping for different modulation levels is provided. The frame rate of the device is also constrained by the phase flicker. The balance between low flicker and fast LC response for fast frame rate is quantitatively analyzed. On the application side, the effects of real phase flicker on the performance of blazed gratings and image holograms are investigated using the temporal phase flicker profiles measured from a phase-only liquid crystal on silicon (LCOS) device; they are shown to be comparable with that introduced by quantization level and amplitude noise, respectively.

Spatial light modulators (SLMs) are key research tools in several contemporary applied optics research domains. In this paper, we present the argument that an open platform for interacting with SLMs would dramatically increase their accessibility to researchers. We introduce HoloBlade, an open-hardware implementation of an SLM driver-stack, and provide a detailed exposition of HoloBlade’s architecture, key components, and detailed design. An optical verification rig is constructed to demonstrate that HoloBlade can provide Fourier imaging capability in a 4f system. Finally, we discuss HoloBlade’s future development roadmap and the opportunities that it presents as a research tool for applied optics.

Owing to the characteristics of existing spatial light modulators (SLMs), the computer-generated hologram (CGH) with continuous complex-amplitude is conventionally converted to a quantized amplitude-only or phase-only CGH in practical applications. The quantization of CGH significantly affects the holographic reconstruction quality. In this work, we evaluated the influence of the quantization for both amplitude and phase on the quality of holographic reconstructions by traversing method. Furthermore, we considered several critical CGH parameters, including resolution, zero-padding size, reconstruction distance, wavelength, random phase, pixel pitch, bit depth, phase modulation deviation, and filling factor. Based on evaluations, the optimal quantization for both available and future SLM devices is suggested.

A modified error diffusion algorithm is proposed for encoding the binary pattern in a holographic display system based on DMD. The proposed method has better display quality than the previous superpixel method.

Using temporal phase flicker profiles of real phase-only LCOS devices, their effects on the performance of blazed gratings and image holograms are shown to be comparable to that introduced by phase quantization and amplitude noise.

The optical characteristics of the photopolymer were analyzed to manufacture the reflection-type full-color holographic optical element (HOE) with uniform diffraction efficiency. Preliminary experimental results confirm that controlling the initial exposure time of three lasers can implement high-efficiency full-color HOE.

A deep neural network that yields 3D multi-focal hologram is presented. The network takes three focal stacks as inputs and yields corresponding real and imaginary parts of a complex hologram.

In this abstract, dynamic flat optical devices with tunable materials like doped semiconductors and functional liquid crystals have been demonstrated such as tunable color filters and stimuli-responsive dynamic metaholograms for advanced display and sensor applications.

In this work we present compact single lens wide angle holographic display with LED illumination, which is capable of reconstructions of large size images. Obtained optical results illustrate high quality images at large depth.

We propose a gradient-based optimization method for time-multiplexed binary holograms displayed on a digital mirror device. Optimized binary holograms can be used to reconstruct high-quality images.

Several types of augmented reality three-dimensional display systems are introduced. All systems consist of a holographic optical element fabricated by wavefront printing technique to be used as an optical functional screen.

A method of beam deflection using decentered lens group based on angle compensation is proposed to enlarge the viewing angle of three-dimensional (3D) image display for holographic projection, based on time-division multiplexing method. © 2021 The Author(s)

We demonstrate phase-only tuning of optical metasurfaces in the full 2p-range by controlling the optical anisotropy of their surroundings. The concept is exemplified in a liquid crystal infiltrated metasurface tuned by the temperature and bias-voltage.

The autostereoscopic 3D display has two important indicators, both the number of viewpoints and display resolution. However, it's a challenge to improve both the viewpoint and the resolution. Here, we develop a fixed-position multiview and lossless resolution autostereoscopic 3D display system that includes the dynamic liquid crystal (LC) grating screen. This display system consists of an LC display panel and an LC grating screen. The synchronization of the frame switching of the LC display panel and the LC grating screen shutter enables the preserved resolution. The "eye space" design makes the viewpoint dense enough and determines the LC grating screen's parameters. Based on the above work, we use binocular viewpoint tracking technology to realize the LC grating screen's adaptive control. Different binocular views are rendered in real-time according to the different positions of a single pair of stereoscopic viewpoints in the eye space, making the motion parallax possible. We present the working principle and mathematical analysis. We implement a prototype for verifying the principle. According to the experiment results analysis, this prototype can achieve viewpoint tracking and motion parallax based on resolution lossless and viewpoint dense enough.

We examine the application of holographic principles in atomic scales by simulating EBSD experiments. First experiments prove the validity of our approach and are presented as examples and as a preview.

Recent integrated optical phased array architectures, results, and applications will be reviewed, including beam steering for LiDAR and communications, near-field optical manipulation, and holographic displays for augmented reality.

We present a method to create the holographic foveated rendering effect based on the iterative phase retrieval algorithm. We validated our proposing algorithm using an optical setup with a multi-phase spatial light modulator.

A wavefront correction technique based on adaptive optics is demonstrated for a holographic display. For different regions of interest in the output image, a phase only SLM displays a pre-compensated hologram that reduces the aberrations.

We propose an automatic registration method for the data obtained by a commercial 3D-tracking sensor and the 3D image reproduced by a light-field display for an aerial 3D-touch interface.

We investigated the optical performance of a specific 3D light field display implementation using Zemax software in terms of wavefront error and imaging parameters including spot size, lateral color, Strehl ratio, and point spread function.

Next generation displays have to resolve major design challenges for providing frictionless user experiences. To address these issues, we introduce two concepts named as “Beaming Displays” and “Patch Scanning Displays”.

I will introduce the details of our slim-panel holographic video display, and discuss the issues and directions to improve it towards holographic flat panel displays. © 2021 The Authors

Noise filtering system is an essential part of a holographic display, but it hinders to achieve a compact form factor. We suggest a whole design of a holographic see-through head-mounted display with a compact Bragg DC filter.

We present a hardware architecture for generating Fresnel holograms for 3D holography on a small scale field-programmable gate arrays. Our hardware implementation can achieve similar performance to a high-end CPU enabled software implementation.

An integral imaging near-eye display with off-axis concave mirror holographic optical element is reported. 3D image formation with focal cue is demonstrated. An aberration compensation for this tilted system will also be covered in the presentation.

We present a carrier envelope phase (CEP) stable system capable of arbitrary intensity, phase, and spin angular momentum distributions based on the principles of free-space coherent synthesis.

We will discuss optical architectures for holographic flat panel displays and present some of our approaches to implement the slim holographic display.

An improved method to accelerate CGHs computation based on accurate high compressed look-up-table method is proposed. Numerical results show proposed method is an effective method to calculate CGHs with high speed and low memory usage.

Direct coding of light field images for high-resolution holographic 3D display is proposed. Two high-resolution holograms for static 3D display and multi-view dynamic 3D display are calculated and optically reconstructed to approve the validate of proposed method. © 2020 The Author(s)

In this paper, we propose computer-generated hologram calculation method for pentile display panel. In order to compensate non-orthogonal pixel struchrre, the CGHs for the even and odd rows of pixels are calculated separately and combined again with proper compensation term. The proposed method is verified by simulation and experimental results.

Holographic augmented reality near-eye display using an eyepiece made of Pancharatnam-Berry phase lenses is proposed. Adopting Pancharatnam-Berry phase lenses makes it possible to construct a large field of view near-eye display with a focus cue.

We present a method to generate uniform energy signal wave without energy loss for holographic display. The proposed method was confirmed by experiments. Experimental results show that the reconstructed signal wave has flat energy envelope.

A resampled macro-pixel double-phase method to encode complex holograms is proposed. The reconstruction noise of the double-phase holograms is suppressed with the same hologram size, which is validated in numerical simulations and optical experiments.

We present a new type of achromatic metalenses consisting of inversely designed random-shaped meta-atoms. The inverse design algorithm makes the designs not limited to human cognitive capabilities.

We developed dedicated processors for holography named ‘HORN,” which accelerate hologram calculation by parallelizing many calculation units. If we reduce the calculation accuracy of the units, the circuit size of the units decreases, which in turn leads to an increase in the number of the units; however, owing to this the image quality degrades. In this study, we propose a dedicated processor with low accuracy units assisted by a deep neural network (DNN). After performing the hologram calculation in the processor, we restore a high accuracy hologram from the low accuracy one using the DNN.

Usually, achieving full-color holographic 3D display consumes a lot of resources. In order to solve the problem, a lightweight full-color holographic 3D display system using a single SLM based on color-dispersion compensation method is proposed.

We demonstrate the design and 3D printing of a large-scale complex-amplitude metasurface hologram for orbital angular momentum-multiplexing holography. The independent and complete amplitude and phase manipulation allows the lensless reconstruction of 200 OAM-dependent orthogonal image frames for holographic videos displays.

We demonstrate miniature silicon nitride (SiN) pure-phase modulators operating at the blue wavelength. The devices are based on adiabatic micro-rings that are robust against fabrication variations and hold great promise for large-scale visible integrated systems.

We propose a method to generate holograms using a deep neural network. The proposed network can generate complex holograms from slice images of different depths. It is verified that the images reconstructed from the hologram can be formed at two depths.

We propose multiple point cloud gridding and parallel computing methods to accelerate the full-color holographic system. Compared to conventional methods, the computational complexity is reduced. The feasibility of our method is confirmed numerically and optically.

A curved multiplexing method is proposed to increase the view angle and information capacity. The different objects are reconstructed by bending a composite hologram. It is proven to be viable theoretically and experimentally.

we present the synthesis of ultrashort laser bullets with real-time adaptive and programmable field topology, including field amplitude, and linear, spin angular, and orbital angular momenta.

Holography is perhaps the most promising technology to achieve wide field of view compact eye-glasses style near-eye displays. However, the digital hologram computation algorithms are still not perfect and resort to heuristic encoding or iterative methods relying on varying relaxations. In this paper, we deviate from such heuristic solutions to holographic phase retrieval but instead rely on formal optimization that is enabled by complex Wirtinger gradients. We pose the entire hologram computation forward model as a differentiable forward model and formulate a quadratic loss function that is solved via firstorder optimization methods. Using this framework, we achieve holographic reconstructions with an order of magnitude improved image quality, both in simulation and on an experimental prototype.

This paper discusses reconstruction of synthetic aperture Fourier hologram with unitary sampling on the SLM with non-squared pixel structure. A numerical procedure is introduced to meet different sampling ratio of the hologram. Experimental verification is provided.

Holographic displays promise unprecedented capabilities for direct-view displays as well as virtual and augmented reality applications. We develop Neural Holography, an algorithmic computer-generated holography (CGH) framework that uses camera-in-the-loop training to achieve unprecedented image fidelity and real-time framerates.

The light field image acquisition for the holographic stereogram printing method is proposed. Cameras capture the high-resolution perspectives while they are shifted; then utilized as sources in the image processing for holographic stereogram printing.

A phase added stereogram method that allows calculation of computer-generated holograms that have large horizontal parallax is developed. It is shown that our method can synthetize large holograms with high computational efficiency.

We present an optical apparatus made of two Fresnel mirrors facing each other, a counteipart of the mirascope used in 360-degree viewable volumetric displays. Based on the derived theory, the magnifications can be altered.

Recent integrated optical phased array architectures, results, and applications will be reviewed, including beam steering for LiDAR and communications, near-field optical manipulation, and holographic displays for augmented reality.

Computer-generated holography suffers from high diffraction orders (HDOs) created from pixelated spatial light modulators, which must be optically filtered using bulky optics. Here, we develop an algorithmic framework for optimizing HDOs without optical filtering to enable compact holographic displays. We devise a wave propagation model of HDOs and use it to optimize phase patterns, which allows HDOs to contribute to forming the image instead of creating artifacts. The proposed method significantly outperforms previous algorithms in an unfiltered holographic display prototype.