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Polarization is the nature of optics. Exploiting metasurface's polarizations can enhance the multiplexing capacity but face a limited number of channels. For example, a single‐layer metasurface can offer three independent channels with six degrees of freedom (DoFs) including the amplitude and phase of Ex, Exy(yx), and Ey of the Jones matrix. In this work, it is theoretically demonstrated that the degrees of freedom of dual‐layer metasurfaces can reach eight, overcoming the polarization multiplexing constraints of single‐layer metasurfaces and that the cross‐talk can be largely reduced as compared with single‐layer metasurfaces when the channel number is larger than three. Numerical calculations manifest a decrease of 100%, 63%, and 50% for the cross‐talk of channels 4, 5, and 6, respectively. As a proof‐of‐concept demonstration of high‐capacity polarization multiplexing, an arbitrary‐polarization‐controlled 5‐channel dual‐layer metasurface exhibiting five nanoprintings and five holographic images with reduced cross‐talk under different incident and output polarizations is successfully designed. Thus, the research highlighting the high‐multiplexing‐capacity of dual‐layer metasurfaces can significantly advance multifunctional optical devices with high efficiency, simple integration, and ease of manipulation. [ABSTRACT FROM AUTHOR]

Holographic imaging as one of promising image techniques reconstructs object image using the amplitude and phase information scattered from objects. Programmable metasurface composed of digitally coding unit cells can arbitrarily manipulate amplitude and phase of the scattering wave by tailoring operation states of the unit cells, and thus achieves high‐resolution imaging reconstruction. However, the conventional metasurface can only achieves a desired holographic image on an imaging plane. This paper presented a time‐space coding 2‐bit metasurface to overcome this challenge. By rapidly switching PIN diodes loaded in metasurface unit cell according to the customized time sequences, the magnitude and phase of the ±1st order harmonic fields can be fully controlled, achieving the hologram imaging at the higher order harmonics. The proof‐of‐concept measurements are given to demonstrate the versatile holographic imaging functions at the ±1st order harmonics including two different holographic images on an imaging plane, holographic imaging and beam scanning, and holographic imaging and orbital angular momentum (OAM) wave generation, which undoubtedly enriches the applications of the programmable metasurfaces in the field of the holographic imaging. [ABSTRACT FROM AUTHOR]

Phase manipulation plays a fundamental role in electromagnetic (EM) and optics research, i.e., the wavefront shaping depends heavily on phase modulation. However, the previous phase manipulation methods are limited to phase‐angle dimensionality, and the magnitude and phase are generally deemed as two distinct characters that should be controlled separately. Herein, a phase manipulation method in which phase is modulated by magnitude is proposed that follows an EM expression of Euler's formula. A rotation phase of linearly‐polarized waves is presented. Using this method, several unique applications in this research are demonstrated. First, a Hall effect of non‐angular‐momentum waves is obtained; second, an interdigital topology model with a unique topological‐charge control strategy is presented; and finally, the method is applied to holographic imaging, of which information of the hologram is recorded as a distribution of magnitude. Furthermore, as this method is applicable to all forms of harmonic waves, it can be potentially applied to other areas of wave phenomena such as acoustics and mechanics. [ABSTRACT FROM AUTHOR]

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The mitochondrial permeability transition pore (mPTP) is a large, weakly selective pore that opens in the mitochondrial inner membrane in response to the pathological increase in matrix Ca2+ concentration. mPTP activation has been implicated as a key factor contributing to stress-induced necrotic and apoptotic cell death. The molecular identity of the mPTP is not completely understood. Both ATP synthase and adenine nucleotide translocase (ANT) have been described as important components of the mPTP. Using a refractive index (RI) imaging approach, we recently demonstrated that the removal of either ATP synthase or ANT eliminates the Ca2+-induced mPTP in experiments with intact cells. These results suggest that mPTP formation relies on the interaction between ATP synthase and ANT protein complexes. To gain further insight into this process, we used RI imaging to investigate mPTP properties in cells with a genetically eliminated C subunit of ATP synthase. These cells also lack ATP6, ATP8, 6.8PL subunits and DAPIT but, importantly, have a vestigial ATP synthase complex with assembled F1 and peripheral stalk domains. We found that these cells can still undergo mPTP activation, which can be blocked by the ANT inhibitor bongkrekic acid. These results suggest that ANT can form the pore independently from the C subunit but still requires the presence of other components of ATP synthase. [ABSTRACT FROM AUTHOR]

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.

A floating signage which means optical images are floating in the air is one of the useful ways to attract people's attention. Since 2019, our research group proposed unidirectional observable aerial signage display using thin film layers or dye-dopedoptical prisms to avoid mirrored imaging problem which means observers end up watching wrong messages or images from back side. In this paper, the authors describe the aero signage using quasi-spatial floating image and how to generate floating images using optical illusion and to control light paths. [ABSTRACT FROM AUTHOR]

It stands to reason that someone observes mirrored imaging according to the direction of viewing if you draw something on the transparent material. The authors dislike this mirrored imaging problem, although it is not a fatal defect. In 2021, our research group proposed window signage using dye‐doped thin film layer to avoid this problem of mirrored imaging. But our 2021 model had a defect that the transparency of a glass window with half mirror layer was less than the general glass material without half mirror because of image generating mechanism. To solve this "reflect surroundings" problem, we needed to find new technology for generating color using a transparent material. This paper shows a unidirectional observable window signage using holographic imaging or holographic optical elements for unidirectional color generating by light controls, how to make structural colors using holographic recording technology and material development. [ABSTRACT FROM AUTHOR]

How to realize acoustic holography via ultradeep‐subwavelength structures is a challenging problem in the past decades, which is thought impossible due to the linear proportional relationship between the structural thickness and acoustic wavelength. In this article, the methodology of ultrathin holography by patterning holes in an acoustic insulation plate with an ultradeep‐subwavelength thickness is introduced. The transmitted sound field can be manipulated arbitrarily to form a desired shape by designing the ultrathin pattern based on the nonlocal wave interaction theory. The physical mechanism of the nonlocal behavior to achieve a sophisticated hologram is revealed due to the interaction among the sound wave components themselves. Furthermore, the experiments are designed to map out the pressure amplitude field of a "sun" pattern in air and water, respectively. The work demonstrates the advantage of nonlocal ultrathin holography in the applications of ultrathin acoustic devices and provides inspiration for the holographic wave manipulation. [ABSTRACT FROM AUTHOR]

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science. [ABSTRACT FROM AUTHOR]

Abstract How to realize acoustic holography via ultradeep‐subwavelength structures is a challenging problem in the past decades, which is thought impossible due to the linear proportional relationship between the structural thickness and acoustic wavelength. In this article, the methodology of ultrathin holography by patterning holes in an acoustic insulation plate with an ultradeep‐subwavelength thickness is introduced. The transmitted sound field can be manipulated arbitrarily to form a desired shape by designing the ultrathin pattern based on the nonlocal wave interaction theory. The physical mechanism of the nonlocal behavior to achieve a sophisticated hologram is revealed due to the interaction among the sound wave components themselves. Furthermore, the experiments are designed to map out the pressure amplitude field of a “sun” pattern in air and water, respectively. The work demonstrates the advantage of nonlocal ultrathin holography in the applications of ultrathin acoustic devices and provides inspiration for the holographic wave manipulation.

In order to enhance channel capacity in modern wireless communications, diverse multiplexing techniques, such as polarization, frequency, and spatial multiplexing, are proposed and implemented. Here, a non‐interleaved polarization‐frequency multiplexing metasurface is proposed, which can realize independent controls of orthogonal linearly polarized or circularly polarized waves in two frequency bands to achieve four independent information channels. As a proof of concept, the metasurfaces that can independently realize four different polarized holographic images in two frequency bands are designed, simulated, and measured. The results show that two orthogonally polarized holographic images are achieved in each frequency band, respectively, which can be either linear or circular polarization. Benefitting from the advantages of non‐interleaved design, the proposed metasurfaces can reach not only high information capacity but also high information density by taking full use of the metasurface apertures. [ABSTRACT FROM AUTHOR]

Short peptide-based supramolecular hydrogels hold enormous potential for a wide range of applications. However, the gelation of these systems is very challenging to control. Minor changes in the peptide sequence can significantly influence the self-assembly mechanism and thereby the gelation propensity. The involvement of SARS CoV E protein in the assembly and release of the virus suggests that it may have inherent self-assembling properties that can contribute to the development of hydrogels. Here, three pentapeptide sequences derived from C-terminal of SARS CoV E protein are explored with same amino acid residues but different sequence distributions and discovered a drastic difference in the gelation propensity. By combining spectroscopic and microscopic techniques, the relationship between peptide sequence arrangement and molecular assembly structure are demonstrated, and how these influence the mechanical properties of the hydrogel. The present study expands the variety of secondary structures for generating supramolecular hydrogels by introducing the 3 10 -helix as the primary building block for gelation, facilitated by a water-mediated structural transition into β-sheet conformation. Moreover, these Fmoc-modified pentapeptide hydrogels/supramolecular assemblies with tunable morphology and mechanical properties are suitable for tissue engineering, injectable delivery, and 3D bio-printing applications., (© 2024 Wiley‐VCH GmbH.)

Objectives: To demonstrate the potential application of mixed reality (MR) holographic imaging technology in subgingival scaling and root planing (SRP) for patient with advanced periodontitis., Methods: This case series comprised the analysis of 1566 sites from 261 teeth of 10 patients with advanced periodontitis. Digital CBCT scans and intraoral scans of the patients were digitally acquired preoperatively and aligned to create a three-dimensional periodontal visualization model. Through rendering, interactive holographic images were displayed using MR. The surgeon first used MR images to communicate with the patients, and then facilitated SRP under their guidance. Probing pocket depth (PPD), clinical attachment loss (CAL), Plaque index (PI), and bleeding on probing (BOP) parameters were recorded at baseline and at 8-week postoperatively. Patient-reported outcome indicator questionnaires on self-efficacy were also collected., Results: PPD, CAL, PI, and BOP significantly decreased at 8-week following MR hologram-assisted SRP (p<0.001). For sites with PPD≥4 mm, PPD and CAL declined by 2.33±1.23 mm and 0.69±1.07 mm, respectively. PI significantly decreased from 1.94±0.61 to 0.82±0.58 (p < 0.001) and BOP sites decreased significantly from 84.11% to 40.25%. After receiving MR holograms for condition communication, most patients had a better perception of the effectiveness of SRP treatment and the benefits it brings. 80% of the subjects expressed their willingness to undergo MR-assisted periodontal treatment in the future., Conclusion: These results provide preliminary support for MR hologram-assisted digital SRP. With this technology, images of the gingiva and alveolar bone can be displayed in real time, accurately and three-dimensionally. This improves SRP effectiveness, diminishes complications, and enhances patients' confidence in the treatment., Clinical Significance: MR holographic imaging-based digital SRP is a clinically feasible and promising adjunctive periodontal treatment option. It may contribute to improved non-surgical treatment efficacy in patients with severe periodontitis., Competing Interests: Declaration of competing interest The authors declare there is no conflict of interests., (Copyright © 2024. Published by Elsevier Ltd.)

Objectives: To investigate the application effect of mixed reality (MR) holographic imaging technology in the clinical surgical treatment of spinal cord glioma. Methods: The clinical data of 53 patients with spinal cord glioma who underwent surgical treatment in the Neurosurgery Department of our hospital from January 2017 to May 2020 were retrospectively studied. All the patients were divided into two groups according to different assistive technologies during the surgery: the observation group and the control group, with 30 cases and 23 cases respectively. Patients in the observation group received MR holographic imaging technology intraoperatively, while those in the control group received ultrasound. The surgical conditions of the two groups: the rate of complete resection of tumor lesions and the evaluation accuracy of complete resection were compared. Patients were followed up for 12 months in the outpatient department after surgery, and the recovery of postoperative spinal physiological function was evaluated based on imaging review and MMS scale grading, and the recurrence was obtained. Results: There was no statistical significance in the basic clinical conditions between the two groups (P>0.05), and the total tumor resection rate in the experimental group was 96.67%, and that in the control group was 82.61%, showing a statistically significant difference (P<0.05). Based on enhanced MRI examination as the standard, the evaluation accuracy of intraoperative complete tumor resection in the experimental group was 93.33%, significantly higher than that in the control group (73.54%), with a statistical significance (P<0.05). The incidence of postoperative complications was 3.33% in the experimental group and 21.74% in the control group, with a statistically significant difference (P<0.05). Postoperative follow-up showed that good recovery rate of spinal cord function in the experimental group was 56.70%, and that in the control group was 41.09%, with a statistically significant difference (P<0.05). The recurrence rate was 0 in the experimental group and 4.34% in the control group at follow-up, with no statistically significant difference (P>0.05). Conclusions: With the application of MR holographic imaging technology in the surgical treatment of spinal cord glioma, critical clinical value can be realized. Specifically, the resection degree of spinal cord glioma can be displayed in real time, accurately, and three-dimensionally, the effect of surgical resection can be improved, surgical complications can be diminished, and the recovery of spinal cord function can be accelerated. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the clinical value of the holographic imaging technology in combination with robotic-assisted partial nephrectomy (RAPN) for renal hilar tumor treatment. Patients and methods: From Dec. 2018 to Dec. 2021, patients diagnosed with renal hilar tumor were included in this retrospective study. Before the surgery, the engineers established the holographic image models based on the enhanced CT data. The models were used in patient consultation, pre-surgery planning and surgery simulation. During the RAPN, the navigation was achieved by real-time overlapping of the holographic images on the robotic surgery endoscopic views. The navigation technique helped the surgeon to identify the important anatomic structures such as tumor, renal vein, renal artery, and pelvis. Results: There were total of eight patients with renal hilar tumor who underwent RAPN combined with holographic imaging technique. The mean age was 57.3 years, the median ASA score was 2. The mean tumor size was 42.4 mm and the median RENAL Nephrometry score was 9.5. The clinical stages were cT1a (37.5%) and cT1b (62.5%). All the procedures were performed uneventfully by one surgeon. The mean operative time was 144.3 min, and the mean warm ischemia time was 27.9 min. The mean estimated blood loss was 86.3 ml. There was no conversion to open surgery or radical nephrectomy. There were no Clavien–Dindo ≥ 3 perioperative complications. Conclusions: Using the holographic imaging technique, the pre-surgery planning, simulation of renal arterial clamp and excision of the tumor, and intraoperative navigation were feasible and helpful in facilitating RAPN. [ABSTRACT FROM AUTHOR]

Cells need to rapidly and precisely react to multiple mechanical and chemical stimuli in order to ensure precise context‐dependent responses. This requires dynamic cellular signalling events that ensure homeostasis and plasticity when needed. A less well‐understood process is cellular response to elevated interstitial fluid pressure, where the cell senses and responds to changes in extracellular hydrostatic pressure. Here, using quantitative label‐free digital holographic imaging, combined with genome editing, biochemical assays and confocal imaging, we analyse the temporal cellular response to hydrostatic pressure. Upon elevated cyclic hydrostatic pressure, the cell responds by rapid, dramatic and reversible changes in cellular volume. We show that YAP and TAZ, the co‐transcriptional regulators of the Hippo signalling pathway, control cell volume and that cells without YAP and TAZ have lower plasma membrane tension. We present direct evidence that YAP/TAZ drive the cellular response to hydrostatic pressure, a process that is at least partly mediated via clathrin‐dependent endocytosis. Additionally, upon elevated oscillating hydrostatic pressure, YAP/TAZ are activated and induce TEAD‐mediated transcription and expression of cellular components involved in dynamic regulation of cell volume and extracellular matrix. This cellular response confers a feedback loop that allows the cell to robustly respond to changes in interstitial fluid pressure. Synopsis: YAP/TAZ transcriptional co‐activators are central regulators of cellular response to changes in the extracellular and intracellular mechanical environment. This study identifies oscillating hydrostatic pressure as a new regulator of cell volume via YAP/TAZ activation. YAP/TAZ regulate cell volume and plasma membrane tensionOscillating hydrostatic pressure induces rapid and reversible changes in cellular volumeYAP/TAZ activation are essential for the cellular response to hydrostatic pressureCellular response to oscillating hydrostatic pressure involves clathrin‐dependent endocytosis and the actin cytoskeleton [ABSTRACT FROM AUTHOR]

General theory of holographic inversion with linear frequency modulation (GHI-LFM) has been proposed recently, providing the framework for further advances in the holographic methods for image reconstruction with millimeter-wave linear frequency modulation (LFM) radar. Here, accelerated holographic imaging (AHI)-LFM, an AHI method for LFM radar that exploits range stacking, is proposed. The method is developed and validated for the purpose of whole-body security screening. The image quality and the computational efficiency are compared with the original GHI-LFM algorithm. It is demonstrated that the AHI-LFM algorithm improves the reconstruction speed by at least an order of magnitude while preserving the same image quality for the image sizes arising in practical whole-body security screening. [ABSTRACT FROM AUTHOR]

This article proposes a design optimization method of fast compressive sensing (CS) operators for wideband three-dimensional (3-D) millimeter-wave (mmW) imaging systems. The proposed method consists of two parts: 1) a near-orthogonal 3-D mmW imaging operator design for avoiding large precomputed arrays and 2) a random antenna pattern design (compressive binary sampling matrix) for sparse sampling. The 3-D mmW imaging operator takes the nonlinear wavenumber relationship into account and uses a combination of truncation repair and sampling density compensation to eliminate the reconstruction error caused by truncating $z$ and the nonuniform $k_{z}$ sampling. The compressive binary sampling matrix minimizes grating lobes and suppresses residual grating lobes while maintaining the mainlobe width, by maximizing PeakSLL and maxPSF in the respective frequency range and 2-D measurement aperture. A ${Ka}$ -band (35–45 GHz) experiment utilizes the measurements of a very low sampling rate of 6.25% of fully sampled data to recover a high-resolution image. The result shows that the proposed CS operator reduces the maximum reconstruction error and the mean square error (MSE) between the recovered images from undersampled measurement and from the fully sampled data to $10^{-15}$ and $10^{-3}$ , respectively. Furthermore, the proposed decomposition method enables the soft thresholding in the CS iterative algorithms and simplifies the CS implementation in terms of antenna-array patterns, memory usage, and parallel computing. If the imaging system is implemented by a spatial antenna array, then the 6.25% sampling rate means that the number of antennas is reduced to 25% of the full-sampling system, thus reducing the cost. If the imaging system is implemented by raster scanning, then the CS implementation will reduce the number of spatial points to 25%, thus reducing the scan time. The number of frequency points is also reduced to 25%, which reduces the memory usage. [ABSTRACT FROM AUTHOR]

In millimeter-wave imaging systems, the inversion efficiency of both the narrowband and broadband systems is affected by the target's distribution distance. The mismatched distances cause inefficiency of the system, and the recovered images suffer from displacement blur. We analyze in detail the reasons for this phenomenon and propose a simple method to overcome it. Minimizing the sharpness metric of images is a key strategy to solve this problem. Using this method, the exact range information of the target can be obtained from the minimum sharpness of the unknown object, and then, the region of interest of the inversion can be located. Both synthetic and full-wave simulation data demonstrate the superiority of the method. Finally, the efficiency of the method is verified by the in-house developed test system. [ABSTRACT FROM AUTHOR]

This paper proposes a free space optical communication (FSO) receivier system with adaptive alignment based on pure phase holographic imaging. During the frame header transmission period, the optical phased array in this system performs specific holographic imaging on the receiving plane, which assist the system to undergo beam alignment. The system model has been built in this work, along with the receiving signal expression. Based on the physical model, we propose an algorithm for positioning calibration and the circuitous phased encoding for improvement of imaging quality and algorithm complexity.

Holography has been fascinating people for almost 70 years (since Gabor's invention in 1947) as a true three‐dimensional (3D) imaging technology that can replicate 3D scenes in free space. Holography has also led to important developments in physics and technology as manifested by fundamental ideas proposed by renowned scientists and holographers, such as Emmeth Lieth (off‐axis holography), Yuri Denisyuk (reflection holography), Stephen Benton (rainbow holography), and Adolf Lohmann (computer‐generated holograms). Their ideas have been established as essential concepts and have advanced considerably the field of optical and digital holography during the past fifty years. The 21st century is the age of digital technology and tremendous progress in optoelectronics and micro/nanotechnology has been accomplished. This progress has opened the doors for true holographic applications in important areas such as holographic 3D displays with photorealistic visualization, 3D quantitative imaging in biomedicine, optical metrology using digital holographic interferometry, microscopy, and tomography. Successful applications and true holographic products in the market have advanced holography to a level at which standards setting organizations must be involved to guarantee interoperability between devices and applications.

Digital coding metasurface, which provides a new approach to link the physical world and information science, has been quickly developed in recent years. However, all previously reported metasurfaces cannot achieve independent controls of different polarizations in both transmission and reflection spaces at the same time. In this work, a reconfigurable anisotropic digital coding metasurface loaded with electronically controlled PIN diodes is proposed that can independently manipulate not only the near/far‐field pattern but also the transmission and reflection modes of the electromagnetic waves under different polarizations. As a validation example, a multifunctional holographic imaging metasurface is designed, fabricated, and measured. Both simulated and measured results show that orthogonally polarized waves (vertical and horizontal polarizations) can be manipulated to achieve different images, and the transmission and reflection modes of the differently‐polarized images can be independently controlled in real time by changing the state of the loaded PIN diodes. [ABSTRACT FROM AUTHOR]

Introducing compressed sensing theory into the millimeter-wave near-field holographic imaging algorithm, it can break the Nyquist sampling limit, reconstruct the compressed echo signal, and invert the target image. In the reconstruction process, there are defects such as missing target key information, excessive invalid search volume and so on. Aiming at this problem, an adaptive multi-extreme particle swarm optimization (AMPSO) algorithm is proposed. Its advantages are that it can retain more target information, search for more extreme values, and improve the convergence speed. At the same time, the search probability in the strong scattering area is also increased, the search time is avoided in the noise area, and the number of extreme points is adjusted on a global scale. The effectiveness of the algorithm is verified by simulation and actual measurement of multiple types of targets under different experimental conditions. [ABSTRACT FROM AUTHOR]

A self-designed all-solid-state electronic 3-D millimeter-wave imaging radar is demonstrated and applied in holographic imaging for nondestructive testing of polymer materials. Full heterodyne detection is implemented in the system, which is based on a sawtooth linear frequency-modulated continuous wave, with a center frequency of 195 GHz, a bandwidth of 42 GHz, and an average power of 0.5 mW. A suitable calibration method is employed to solve the problem caused by the nonlinearity of frequency modulation. Performance parameters are established experimentally, including range resolution (3.2 mm, better than theoretical value) and lateral resolution, ranging from 1.45 to 4 mm at imaging distances from 10 to 70 mm. Simulation and experimental studies ascertain the effectiveness of the system in examining internal defects in combination with imaging algorithms, a classical range migration algorithm for surface reflection based on free-space Green’s function, and a modified subsurface imaging algorithm based on a rigorous half-space Green’s function. For surface defects and defects inside the material whose refractive index is close to air, the performances of both are similar. However, in imaging interior defects buried in a medium with substantially different refractive indices, the modified algorithm is superior, as illustrated by testing of Teflon blocks containing internal voids. Furthermore, convincing experimental evidence shows that the system can image slightly bent and tilted samples. [ABSTRACT FROM AUTHOR]

The ability of metasurfaces to simultaneously manipulate both the spin and phase of circularly polarized (CP) incident waves has attracted considerable attention from researchers. Here, we propose a reconfigurable double circular split rings (DCSRs) chiral metasurface. By introducing graphene and changing the Fermi level of graphene, dynamic circular dichroism (CD) can be achieved. The calculation results show that when the Fermi level of graphene is increased from 0.1 eV to 1 eV, the CD decreases from 0.72 to 0.09 at 0.839 THz, which provides a CD-tunable spin-controlled method. In addition, based on the graphene-enabled DCSRs, we design two metasurface arrays combining Pancharatnam-Berry (PB) phase and coding metasurface theory to realize terahertz CP wave switchable focusing and spin-controlled multi-pencil beam generation. Furthermore, we demonstrate the application of reflective holography for multiplexing circularly polarized waves. The results of this paper are expected to play a significant role in the future terahertz wireless communication system, multi-spectral imaging, and information encryption fields. • Tunable chiral metasurface achieving spin-selective absorption of EM waves. • Switchable circularly polarized wave focusing with "On" and "Off" states. • Spin-controlled multiple pencil beams generation. • Dual-channel multiplexed circularly polarized wave holographic imaging. [ABSTRACT FROM AUTHOR]

Holographic three-dimensional (3D) imaging of Terra-CottaWarrior model using Fractional Fourier Transform is introduced in this paper. Phase holograms of Terra-Cotta Warrior model are calculated from 60 horizontal viewing-angles by the use of fractional Fourier transform (FRT). Multiple phase holograms are calculated for each angle by adding proper pseudorandom phase to reduce the speckle noise of a reconstructed image. Experimental system based on high-resolution phase-only spatial light modulator (SLM) is built for 3D image reconstruction from the calculated phase holograms. The texture of the Terra-CottaWarrior model is rough. The calculation of rough texture is optimized in order to show better model details. The effects of computing distance and layer thickness on imaging quality are analyzed finally. [ABSTRACT FROM AUTHOR]

Abstract Holography is considered to be the ultimate display technology since it can account for all human visual cues such as stereopsis and eye focusing. Aside from hardware constraints for building holographic displays, there are still many research challenges regarding holographic signal processing that need to be tackled. In this overview, we delineate the steps needed to realize an end-to-end chain from digital content acquisition to display, involving the efficient generation, representation, coding and quality assessment of digital holograms. We discuss the current state-of-the-art and what hurdles remain to be taken to pave the way towards realistic visualization of dynamic holographic content. [ABSTRACT FROM AUTHOR]

Circular dichroism (CD) has gained significant recognition in the field of artificial materials. However, there is still a need for a flexible approach to modulate CD, which would enable spin-selective multidimensional manipulation of terahertz (THz) waves. In recent years, reconfigurable metasurfaces have emerged as a prominent area of research in the field of micro/nanophotonic. This study proposes a novel reconfigurable chiral metasurface utilizing the phase transition properties of vanadium dioxide (VO 2), capable of modulating CD. This metasurface not only realizes the modulation of the Pancharatnam-Berry (PB) phase in two states of VO 2 but also enables the modulation of CD at the dual THz band. Based on the principle of the PB phase to control the phase of the meta-atom, the 3-bit coded metasurface arrays were proposed to achieve high-quality THz holographic imaging. Furthermore, the near-field imaging effect is realized by utilizing the differentiation property of the absorption intensity of chiral CD meta-atom. This multifunctional device, with its simple structure, exhibits tremendous potential for applications in THz holographic imaging, THz circular polarized wave detection, and image encryption. • In this work, a reconfigurable chiral metasurface with dual THz bands CD effect is proposed. • By switching the state of VO 2 , the bandwidth of the CD effect can be expanded, and the CD effect of the dual bands can be regulated. • A 3-bit coded metasurface array utilizing the PB phase is proposed in both states of VO 2 to enable high-quality holographic imaging of the characters "V" "O" and "2". • Leveraging the chiral mechanism of the metasurface, the near-field imaging of the characters "C" "U" "M" and "T" is achieved by utilizing the amplitude difference of absorption at the two THz bands. [ABSTRACT FROM AUTHOR]

• A novel technique to extend the field of view and enhance the resolution of an off-axis digital holographic system simultaneously, using a multifunctional holographic optical element is presented. • The main advantages of the proposed digital holographic system include a simple optical setup, Compact size, and Cost-effectiveness due to the use of fewer optical elements. • The system's feasibility demonstrates its ability to increase the field of view and enhance resolution at the same time. • The system's easy-to-set-up experimental configuration and impressive results make it a powerful tool for various optical imaging and empirical research applications. The spatial resolution and field of view (FOV) of the digital holographic system are limited by the finite pixel size of the image sensor. In order to record high-resolution digital holograms of larger objects at a shorter object-to-sensor distance, which is desirable for applications such as display, non-destructive testing, etc., the holographic system must have a larger FOV. We propose a compact off-axis digital holographic setup in which a multifunctional holographic optical element (MHOE) is employed in the path of the object and reference beams to improve the system's resolution simultaneously enhancing the FOV by utilizing the same specifications of the digital sensor. In this configuration, a diffractive optics property of the MHOE enhances the spatial resolution of the optical system. At the same time, the lens function recorded in the same MHOE enables a large imaging area. The experimental results obtained with the proposed configuration are compared to conventional digital holography, where the proposed configuration shows a 423% increase in the FOV. The quality of the reconstructed image with the proposed configuration is measured by calculating the structural similarity index measure (SSIM) value. Experimental results and simulations have verified the feasibility of the proposed system. Furthermore, the proposed system is incredibly compact due to the use of the MHOE. [ABSTRACT FROM AUTHOR]

Millimeter wave (MMW) technology is expanding rapidly into security screening for dangerous items concealed under clothing. It uses safe non-ionizing radiation and penetrates clothing well. We present a new planar system at Ka band for the three-dimensional simultaneous imaging of both sides of an inspected person where the images are produced in real time by a recently proposed generalized holographic reconstruction algorithm. Low-cost linear frequency modulation (LFM) radar technology is used along with a simple but efficient method for system calibration. Experimental characterization of the spatial resolution and the sensitivity of the system prototype has been carried out. It is established that the achieved spatial resolution is 6 mm or better if the item is not obscured by clothing and it may deteriorate to 7 mm depending on the clothing hiding the item. The spatial sensitivity is confirmed to be at least 2 mm.

We discuss and compare three methods to generate holograms for optical tweezers: simple rounding, Floyd-Steinberg error diffusion dithering and mixed-region amplitude freedom (MRAF). These schemes are optimized for producing large arrays of tightly focused luminous spots. The algorithms are compared in terms of their speed, efficiency and accuracy, for periodic arrangements of traps; an arrangement of particular interest for the trapping and manipulation of single laser-cooled atoms in the field of quantum computing. We simulate the image formation using each of a binary amplitude modulating digital mirror device (DMD) and a phase modulating spatial light modulator (PSLM) as the display element. While a DMD allows for fast frame rates, the slower PSLM is more efficient and provides higher accuracy with a quasi-continuous variation of phase. We discuss the relative merits of each algorithm for use with both a DMD and a PSLM, allowing one to choose the ideal approach depending on the circumstances. [ABSTRACT FROM AUTHOR]

Abstract: Self‐propelling disk‐like nanomotor consisting of three metallic segments: a non‐catalytic gold (Au), central magnetic nickel (Ni), and a catalytic platinum (Pt), is designed and fabricated with a high‐efficiency layer‐by‐layer (LbL) deposition method based on the nano‐electro‐mechanical systems (NMES) technology. A bubble propulsion mechanism, resulting from bubble growth and collapse, is proposed to explain the locomotion of the nanomotor suspended in hydrogen peroxide (H2O2) solution. The autonomous propulsion of Au‐Ni‐Pt nanomotor is characterized by digital holographic imaging and analyzed using Matlab, revealing that oxygen (O2) bubbles are generated and detached from the surface of Pt. In addition, the holographic images are for the first time used to reconstruct the instantaneously three‐dimensional (3D) location and trajectory of the nanomotor. [ABSTRACT FROM AUTHOR]

Light-field imaging and holographic imaging are currently the two mostly investigated 3-D imaging technologies because of their potentials to create the viewing environment conforming to a natural viewing condition. The basic optical geometries for image display in these imaging are not different from that of integral photography. The images in the two type of imaging are a set of different view images. These images are arranged as a 2-D point image array, and each point image is expanded with a certain angle to form a viewing zone. The differences between the two types of imaging are the number of point images in the array and the physical entities forming the images. Holographic imaging has many more point images than light-field imaging, and each image in the array consists of coherent right rays from different positions of an object. In light-field imaging, an array of pixels represents a direction view of the object. Despite these differences, they share the same goal of providing a continuous parallax to viewers and require display panels of almost the same characteristics. It is expected that in the future these two imaging techniques will be integrated into the same flat panel along with the plane image. [ABSTRACT FROM AUTHOR]

A label-free, high content, time-lapse holographic imaging system was applied to studies in pharmaceutical compound development. Multiple fields of cellular images are obtained over typically several day evaluations within standard CO2 incubators. Events are segmented to obtain population data of cellular features, which are displayed in scattergrams and histograms. Cell tracking is accomplished, accompanied by Cartesian plots of cell movement, as well as plots of cell features vs. time in novel 4-D displays of X position, Y position, time, and cell thickness. Our review of the instrument validation data includes 1) tracking of Giant HeLa cells, which may be undergoing neosis, a process of tumor stem cell generation; 2) tracking the effects of cell cycle related toxic agents on cell lines; 3) using MicroRNAs to reverse the polarization state in macrophages to induce tumor cell killing; 4) development of liposomal nanoformulations to overcome Multi-Drug Resistance (MDR) in ovarian cancer cells; and 5) development of dual sensitive micelles to specifically target matrix metalloproteinase 2 (MMP2) over-expressing cell lines. © 2017 International Society for Advancement of Cytometry [ABSTRACT FROM AUTHOR]

Electromagnetic holographic data are characterized by two modes, suggesting that image reconstruction requires a dual-mode sensitivity field as well. We analyze an electromagnetic holographic field based on tomography theory and Radon inverse transform to derive the expression of the electromagnetic holographic sensitivity field (EMHSF). Then, we apply the EMHSF calculated by using finite-element methods to flow simulations and holographic imaging. The results suggest that the EMHSF based on the partial derivative of radius of the complex electric potential φ is closely linked to the Radon inverse transform and encompasses the sensitivities of the amplitude and phase data. The flow images obtained with inversion using EMHSF better agree with the actual flow patterns. The EMHSF overcomes the limitations of traditional single-mode sensitivity fields. [ABSTRACT FROM AUTHOR]