Holographic Research Articles

Mixed Reality (Holography)-Guided Minimally Invasive Cardiac Surgery—A Novel Comparative Feasibility Study

The operative field and exposure in minimally invasive cardiac surgery (MICS) are limited. Meticulous preoperative planning and intraoperative visualization are crucial. We present our initial experience with HoloLens® 2 as an intraoperative guide during MICS procedures: aortic valve replacement (AVR) via right anterior small thoracotomy, coronary artery bypass graft surgery (CABG) via left anterior small thoracotomy (LAST), and pulmonary valve replacement (PVR) via LAST. Three-dimensional (3D) segmentations were performed using the patient’s computer tomography (CT) data subsequently rendered into a 3D hologram on the HoloLens® 2. The holographic image was then superimposed on the patient lying on the operating table, using the xiphoid and the clavicle as landmarks, and was used as a real-time anatomical image guide for the surgery. The incision site marking made using HoloLens® 2 differed by one intercostal space from the marking made using a conventional surgeon’s mental reconstructed image from the patient’s preoperative imaging and was found to be a more appropriate site of entry into the chest for the structure of interest. The transparent visor of the HoloLens® 2 provided unobstructed views of the operating field. A mixed reality (MR) device could contribute to preoperative surgical planning and intraoperative real-time image guidance, which facilitates the understanding of anatomical relationships. MR has the potential to improve surgical precision, decrease risk, and enhance patient safety.

High‐Isolation Multidimensional Holography Multiplexing in Non‐Interleaved Metasurfaces

AbstractMetasurfaces have revolutionized holography by enabling high‐density channel multiplexing, positioning them as promising candidates for applications in full‐color holographic imaging, optical data storage, and encryption. However, conventional non‐interleaved metasurfaces face limitations in the number of controllable dimensions, restricting the channels available in each dimension. Here, a novel high‐dimensional multiplexing scheme is introduced that significantly enhances both the channel multiplexing capacity and isolation in non‐interleaved metasurfaces. By integrating the Rayleigh‐Sommerfeld diffraction (RSD) formula into the Gerchberg‐Saxton (GS) algorithm and incorporating gradient descent optimization, the approach achieves precise phase profile control across multiple dimensions—extending the controllable parameters to include wavelength, polarization state, and spatial distance. This method enables simultaneous multiplexing of three polarization channels, three wavelength channels, and two focal plane distances, producing a total of 18 distinct, well‐isolated holographic channels with minimal crosstalk. These results showcase the powerful channel multiplexing and isolation capabilities of this non‐interleaved metasurface design, underscoring its potential to advance optical color imaging, secure data storage, and high‐capacity information transmission, thereby contributing to the development of next‐generation intelligent optical devices.

Detection of ceramic stress intensity factor based on digital holography

This study investigates the application of digital holography in investigating fracture problems of the ceramic material magnesium oxide under three-point bending fracture experiments. A digital holographic optical path system was constructed for this purpose. Three-point bending experiments were performed on magnesium oxide samples using the system, with holograms of the specimens recorded both before and after the application of loads. By utilizing the angular spectrum diffraction reconstruction algorithm, we obtained the complex amplitude of the object wave under varying load conditions and computed the phase changes of the object wave corresponding to different loads. Subsequently, we derived interference fringes from these phase changes, enabling the measurement of the stress intensity factor of magnesium oxide through holographic interferometry and plane stress theory. A comparison of the experimental measurements with theoretical values demonstrates that digital holographic technology is a viable method for measuring the stress intensity factor of ceramic magnesium oxide.

Liquid crystal-based image holography with broadband response and polarization insensitivity.

We propose and experimentally demonstrate liquid crystal-based computer-generated image holography enabled by the Pancharatnam-Berry phase modulation. Such a device exhibits distinctive properties, such as natural light illumination, polarization insensitivity, broadband optical response, high polarization conversion efficiency, and direct visibility to the naked eye. These unique attributes make this type of image holography a promising avenue for applications in optical information storage, anti-counterfeiting, and advanced information displays.

Single-cell bilayer design of a terahertz six-channel metasurface for simultaneous holographic and grayscale images

Metasurfaces have exhibited excellent capabilities in controlling main characteristics of electromagnetic fields. Thus, a lot of significant achievements have been attained in many areas especially in the fields of hologram and near-field imaging. However, some of these designs are implemented in a manner of interleaved subarrays that complicates the design and makes them difficult to achieve integration. Here, an innovative stacking technique of metasurface is combined with vanadium dioxide (VO2) to achieve independent imaging of six channels in terahertz band. Our research combines intensity modulation controlled by the Malus’s law and phase modulation of geometry and propagation to merge amplitude, phase, and polarization manipulation of electromagnetic wave. A “six-in-one” meta-device is constructed by combining phase change properties of VO2 to realize simultaneous near-field grayscale imaging and far-field holography. This design has advantages of wide bandwidth and low crosstalk. Based on the advantage of low crosstalk, single-cell bilayer design allows the number of independent channels to be doubled within an acceptable error range. The proposed metasurface introduces a fresh viewpoint for the design of multi-purpose meta-devices, and has broad application prospects in information encryption and multi-channel image display.

The Road to Commercializing Optical Metasurfaces: Current Challenges and Future Directions.

Optical metasurfaces, components composed of artificial nanostructures, are recognized for pushing boundaries of wavefront manipulation while maintaining a lightweight, compact design that surpasses conventional optics. Such advantages align with the current trends in optical systems, which demand compact communication devices and immersive holographic projectors, driving significant investment from the industry. Although interest in commercialization of optical metasurfaces has steadily grown since the initial breakthrough with diffraction-limited focusing, their practical applications have remained limited by challenges such as, massive-production yield, absence of standardized evaluation methods, and constrained design methodology. Here, this Perspective addresses the challenges in commercialization of optical metasurfaces, particularly focused on mass production, fabrication tolerance, performance evaluation, and integration into commercial systems. Additionally, we select the fields where metasurfaces may soon play significant roles and provide a perspective on their potentials. By addressing the challenges and exploring the solutions, this Perspective aims to foster discussions that will accelerate the utilization of optical metasurfaces and further build near-future metaphotonics platforms.

Ferrofluid‐Assisted Dynamic Metasurface 3D Holography Endowed With Rapid, Linear, and High‐Contrast Color Modulation

AbstractMetasurface holography offers a highly promising approach for naked‐eye, full‐color, 3D displays. However, the natural static structure and material of the metasurface limit its ability to dynamically regulate the light field, posing a challenge for achieving photorealistic 3D holography. Here, a ferrofluid‐assisted dynamic metasurface is first demonstrated, conducting a 3D holography endowed with rapid, linear, and high‐contrast color modulation. The ferrofluid has nano‐structural control properties (flow behavior of nanoparticles and emulsion) that enable dynamic manipulation of the extinction (absorption and scattering) intensity in micron region across a broadband spectrum range (400–850 nm). By integrating the ferrofluid with a broadband metasurface, a novel dynamic meta‐hologram is created, which can not only regulate both amplitude and phase of the light field under a single wavelength laser but also in situ linearly changing the color of holographic images under multi‐wavelength lasers. This method provides a new perspective for implementing dynamic metasurface 3D holography capable of continuous color response.

Large screen size transparent display using spectrum expanded light field holograms.

Holographic displays have the potential to reconstruct natural light field information, making them highly promising for applications in augmented reality (AR), head-up displays (HUD), and new types of transparent three-dimensional (3D) displays. However, current spatial light modulators (SLMs) are constrained by pixel size and resolution, limiting display size. Additionally, existing holographic displays have narrow viewing angles due to device diffraction limits, algorithms, and optical configurations. To overcome these obstacles, we propose a transparent large-size light-field holographic display system. This system utilizes a spectrum-expanded light-field holography algorithm that decomposes the light field in the spectrum domain according to each viewing angle. The spectrum is expanded by a factor of 3. The proposed algorithm widens the viewing angle of the holographic display and utilizes the full spectrum of the display device to support smooth motion parallax as well as the natural depth of field of the light field. Furthermore, we further enlarge the display size by introducing waveguides, and optimize the far-field display performance of the waveguide. The display size is enlarged to 100 mm compared to the general method. The extended spectrum enhances the diffraction angle on the waveguide's grating, resolving content discontinuity in far-field views. The proposed method allows for a more vivid perception of light fields with motion parallax and depth effects on a large transparent screen.

Interferenceless coded aperture correlation holography for five-dimensional imaging of 3D space, spectrum and polarization

Abstract Interferenceless coded aperture correlation holography (I-COACH) is a robust imaging technique for recovering three-dimensional object information using incoherent holography without two-beam interference. In this study, five-dimensional (5D) imaging along 3D space, spectrum and polarization in I-COACH is proposed and experimentally demonstrated for the first time. The proposed technique exploits the polarization-dependent light modulation characteristics of spatial light modulators to record polarization-dependent intensity distributions, which are distinguished by significant blurring between orthogonal polarization states. 5D I-COACH is implemented by inter-connecting all five dimensions in a single frame, and image recovery is attempted from different configurations of recorded point spread intensity distributions and response-to-object intensity distributions along 5D using recently developed deconvolution techniques. The simulation and experimental results confirm the 5D imaging capabilities of I-COACH. The proposed technique can be a useful tool for birefringence microscopy, and functional and structural imaging applications.

Holographic optical correlator-based single pixel imaging with deep learning image reconstruction

Holographic optical correlator-based single pixel imaging with deep learning image reconstruction

Automatic and accurate phase aberration compensation for digital holographic microscopy system based on one-dimensional weighted curve fitting

Automatic and accurate phase aberration compensation for digital holographic microscopy system based on one-dimensional weighted curve fitting

Speckle‐Free 3D Holography in the Wigner Domain

AbstractComputer‐generated hologram (CGH) provides an approach to modulate the 3D coherent wavefront and has been widely used in many optical applications. Over the past few decades, extensive efforts have been made to design optimization models for high‐quality reconstruction. However, the reconstruction quality is still limited due to the mismatch of the bandwidth between the reconstructed field of interest and the reconstructed complex amplitude field in 3D space. Here, an ideal numerical light field mapping physical model from the hologram plane to the 3D image plane for speckle‐free 3D holography in the Wigner domain is established. With the aid of the Wigner distribution function (WDF), which allows the analysis of a light field from not only the space domain but also the spatial frequency domain, the bandwidth properties of the reconstructed field in 3D space are analyzed, which provides a guideline for the sampling of the reconstructed field to efficiently describe the speckles and artifacts. Accordingly, a comprehensive CGH optimization method in the Wigner domain is proposed to constrain the reconstructed intensity fluctuations without errors and omissions for high‐quality reconstruction. As such, this method enables speckle‐free and artifact‐free reconstruction with a twice improvement in peak signal‐to‐noise ratio (PSNR) and a five times improvement in structural similarity index measure (SSIM) compared to conventional phase‐only holograms. The optical experimental results show that this method paves the road for the future implementation of speckle‐free color 3D holography harnessing the advanced integrated photonic devices, and also offers an efficient and practical route for various optical applications, such as 3D display, optical encryption, beam shaping, optical computing and so on.

Label-free imaging flow cytometry for cell classification based directly on multiple off-axis holographic projections.

Imaging flow cytometry allows highly informative multi-point cell analysis for biological assays and medical diagnosis. Rapid processing of the imaged cells during flow allows real-time classification and sorting of the cells. Off-axis holography enables imaging flow cytometry without chemical cell staining but requires digital processing to the optical path delay profile for each frame before the cells can be classified, which slows down the overall processing throughput. We present a method for real-time cell classification via label-free quantitative imaging flow cytometry using digital holography, offering a comprehensive representation of cellular structures, without the need for digital processing before automatic cell classification. We aim to develop an automatic cell classification scheme based directly on the off-axis holographic projections of the cells during flow and test it for stain-free imaging flow cytometry of white blood cells. After building a dedicated off-axis holographic microscopy system for acquiring white blood cells during flow, we apply deep-learning classification directly in the off-axis hologram space, rather than in the quantitative phase profile space. This way, we simplify computational processes and allow a significant increase in the cell classification throughput. In addition, by utilizing multiple-viewpoint holographic projections of the cells rotated during flow, instead of using a single projection, we obtain better classification results due to the additional cellular information gained. Our technique demonstrates increasing accuracy with additional viewpoint holographic projections from the optical system, achieving a 7.69% improvement when processing ten interferometric projections compared with a single interferometric projection (regular off-axis hologram). Our technique also outperforms using multiple optical path delay profile projections, requiring off-axis holographic digital preprocessing, by 17.95%, because the holographic projections are analyzed directly without preprocessing and includes the amplitude information as well. Our cell classification approach has great potential for high-throughput, high-content, label-free imaging flow cytometry for classification of large-scale cellular datasets and real-time cell classification during flow in clinical settings.

Multi-functional broadband diffractive neural network with a single spatial light modulator

Diffractive neural networks (DNNs) are emerging as a novel optical computing architecture that combines wave optics with deep-learning methods for high-speed parallel information processing. Herein, we report a reflection type, multi-functional, broadband DNN design. It consists of two phase-modulation layers based on a single spatial light modulator and a mirror facing it. The power efficiency of this design is more than 16 times higher than that of the cascaded structure utilizing beam splitters. It can function either as a two-layer DNN or a one-layer DNN with the other serving as an information input layer. Single- and dual-wavelength filtering and focusing, as well as spatial wavelength demultiplexing of supercontinuum, are experimentally demonstrated using the two-layer DNN, whereas the one-layer DNN is experimentally demonstrated by the classification of hand-written digits, which are input by the first layer via holographic imaging. The designed DNN could operate independently or be readily integrated with other optical systems and may find applications in spectroscopy, microscopy, and information technology.

Viewing the holographic image of the Bardeen-AdS black hole

Viewing the holographic image of the Bardeen-AdS black hole

YOLO-PAS: Detection of Mixed Impurity Particles in Transformer Oil Based on Lens-Free Holographic Imaging and Improved YOLO

YOLO-PAS: Detection of Mixed Impurity Particles in Transformer Oil Based on Lens-Free Holographic Imaging and Improved YOLO

Monte–Carlo Techniques Applied to CGH Generation Processes and Their Impact on the Image Quality Obtained

ABSTRACTComputer graphics aim to create visual representations for screens, where depth is simulated. In contrast, Computed Generated Holograms (CGH) focus on encoding and recreating light patterns to generate a true 3D holographic image that appears as a physical object in space. Therefore, although both use digital models, the computation of CGHs necessitates additional phase‐related calculations, which in turn escalate computational demands. These calculations often result in excessively long development times or, at worst, render the process unfeasible. In order to reduce computational time, Partial Monte–Carlo Sampling (PMCS) techniques for CGH generation are presented, integrating them into the whole process of generating a CGH for a synthetic 3D scene, from design to rendering. PMCS is based on the random choice of a subset of rays used to compute the CGH and relates the computation time spent to the quality of the reconstructed scene. Quantitative analysis shows that PMCS does not significantly compromise image quality. Both simulated and in‐laboratory image reconstruction from holograms demonstrates consistent trends, showcasing improved quality with higher numbers of rays and increased resolution. Furthermore, we establish a direct relationship between image quality and computational time, which effectively addresses specific requirements.

An Exploration of Artificial Intelligence (AI) Integration with Real-Time Three 3-Dimensional Holography to Enhance Visual Quality, Optimize Processing Efficiency, and Facilitate Interactive Applications

This paper explores the integration of artificial intelligence (AI) with real-time 3D holography to enhance visual quality, optimize processing, and enable interactive applications. AI-driven holography significantly improves rendering, object recognition, and user interaction. Recent advances show potential in healthcare, education, and entertainment. This study synthesizes current research on AI-powered hologram generation and highlights the primary challenges and future directions. The focus is on utilizing AI to generate high-quality, interactive holograms that respond dynamically to user inputs. Advances in AI and holography enable new, immersive experiences across fields like entertainment, education, and healthcare. In graphics, the abstract contains a single, concise, pictorial, and Visual summary of the findings of the main articles. It will occur either as the concluding figure from the piece or a figure, especially an idea to capture the content of the articles for readers at a single glance. They were previously drawn, painted, and designed, and the stone building was created by hand without the use of any tools. Present with the help of technology devices like photography, and computer technology we can design as per our interest like MATLAB software. The coming generation we going touch screen displays like hologram 3d graphics. A new method we can use is known as Tensor holography, Holograms could be produced using smartphone software that can be used for virtual reality, 3D printing, medical imaging, and other uses.

Reviving the Ruins of Berenice in the Sidi Khrebish Area of Benghazi Old City by Using Holographic Technology

The city of Benghazi contains rich archaeological and historical monuments that form the spirit of the city, its civilization, and its ancient history, which needs to be preserved and revived in order to preserve the cultural and historical heritage of the city and its buildings and sites. Sometimes preservation involves many different aspects, such as celebrating events, people, places, and ideas that we are proud of. It also sometimes involves recognizing moments in our history that can be painful or uncomfortable to remember. Sidi Khreibish is an archaeological area of important historical value for the Old City of Benghazi in particular and for the city of Benghazi in general. Through the lighthouse, which constitutes the main landmark, it needs to be revived and presented again. With the technical development in the use of technology in architecture, especially in virtual reality and simulation applications, it has become possible to create a virtual environment using technology to reformulate the architectural and urban heritage. This is done by illusioning the recipient’s eye with non-existent 3D models or surfaces that are shaped in a vacuum using advanced hologram techniques and presenting it as a default model. The current study included an integrated analysis of the study area and how the holographic imaging technique could be used, which has a unique feature that enables it to recreate the image of the original objects in its three dimensions to a very high degree, in order to re-embody the Old City and highlight its features of great historical value for the region and revive it within the fabric of the urban city. KEYWORDS: , , , .

Holographic Einstein Rings of AdS Black Holes in Horndeski Theory

Abstract By utilizing the AdS/CFT correspondence and wave optics techniques, we conducted an extensive study of the imaging properties of holographic Einstein rings in the context of Anti-de Sitter (AdS) black holes (BHs) in Horndeski theory. Our results indicate that the optical characteristics of these holographic Einstein rings are significantly influenced by the observer's position, the physical parameters of the BH, the nature of the wave source, and the configuration of the optical system. Specifically, when the observer is positioned at the north pole of the AdS boundary, the holographic image prominently displays a ring structure aligning with the BH's photon sphere. We thoroughly analyzed how various physical parameters---including the observation position, event horizon radius, temperature, and the parameter $\gamma$ in Horndeski theory---affect the holographic Einstein rings. These parameters play a crucial role in determining the rings' radius and brightness, with variations potentially causing the ring structures to deform or even transform into bright spots. Furthermore, our comparative analysis between wave optics and geometric optics reveals a strong agreement in predicting the positions and brightness of both the photon ring and the Einstein ring. This research offers new insights into the spacetime geometry of BHs in Horndeski theory and proposes a promising framework for exploring the gravitational duals of strongly coupled systems.