Independent Phase Research Articles

A wavefront processing coding metasurface with independent dynamic control of circularly and linearly polarized

To address the current issue of complex coding metasurface structure and deficiency of independent phase control for distinct polarized light within the broadband range, we present a wavefront processing coding metasurface with independent dynamic control of circularly and linearly polarized. The results demonstrate that when VO2 is in the metallic state and circularly polarized (CP) is incident, the metasurface can achieve efficient broadband circular polarization conversion in the 0.48–1.19 THz range, with a relative bandwidth of 85.02 %. It can achieve full 0-2π phase coverage by leveraging the P-B phase principle. When VO2 is in the dielectric state and linearly polarized (LP) is incident, x-LP can attain full 0-2π phase coverage in the range of 1.54–1.60 THz and y-LP can reach full 0-2π phase coverage in the range of 0.65–1.05 THz, which can be adjusted independently. Through encoding and arranging the metasurface, abnormal reflection and vortex beam generation of different polarized light in the same device are realized.

Wide-angle reflection control with a reflective digital coding metasurface for 5G communication systems

Abstract Metasurfaces have attracted widespread attention in recent years due to their powerful electromagnetic wave manipulation capabilities. This paper proposes and validates a single-polarized, angle-adjustable reflective digital coding metasurface. Each unit cell achieves independent reflection phase control by loading a PIN diode for on-off switching. The unit’s design and coding scheme are carefully optimized to ensure the performance of the proposed reconfigurable metasurface. As a validation, a prototype consisting of 16×16 elements is fabricated and measured, with a control signal provided by a field-programmable gate array controller. Experimental results demonstrate angle control of up to ±60° in the frequency range of 3.4 GHz–3.6 GHz, a peak gain of 24.9 dBi in a single channel, and gain exceeding 10 dBi across a 200 MHz operational bandwidth. Furthermore, the performance is validated in a communication system, yielding positive results. The proposed reflective digital coding metasurface contributes to the advancement of reconfigurable intelligent surfaces and holds promise for widespread adoption in various communication scenarios.

Polarization insensitive non-interleaved frequency multiplexed dual-band Terahertz coding metasurface for independent control of reflected waves

Independent control of electromagnetic (EM) waves by metasurfaces for multiple tasks are highly desired and is the recent hot topic of research. In this work we contribute a polarization insensitive frequency multiplexed 2-bit coding metasurface to control the Terahertz (THz) waves in the two operating bands independently. In this regard, as a first step a cascaded meta-atom composed of square rings and/or square metallic patches separated by two polyimide substrates is designed and optimized that provides sixteen independent distinct discrete phases in the reflection geometry. These meta-atoms are then distributed with distinct coding sequences in the two-dimensional spatial plane to realize various bi-functional metasurfaces. As a proof of the concept various full structures are designed and simulated to realize a series of bi-functionalities including anomalous reflection/beam shaping, beam shaping/anomalous reflection, beam deflection/Orbital angular momentum (OAM) beam generation with distinct modes and propagating wave to surface wave (PW–SW) conversion/PW beam manipulation in the lower and higher THz bands, respectively. All the simulation results are in excellent agreement with their theoretical equivalents. We envision that the proposed meta-designs have potential applications for the multi-spectral control of EM waves in THz band. The idea can be further extended to design frequency dependent tri-functional and multi-functional THz meta-devices.

Anisotropic vanadium dioxide-based metasurfaces for polarization-multiplexed holograms in the terahertz region

Abstract Holography plays a significant role in optical research and has been utilized in numerous applications. Metasurface holograms are attracting more and more attention with the advancement of their efficient wavefront reshaping. However, the realization of multi-channel holograms and dynamic switching of them still remain challenging in the terahertz band. In this paper, anisotropic vanadium dioxide (VO2) metasurfaces are used to realize four-channel holograms at 1.5 THz. It is assembled by a set of VO2 meta-atoms with independent phase control for different channels. Depending on the polarization of incident wave and the state of VO2, four channels are independently selected. After optimization to eliminate crosstalk between top and bottom layers, two holograms are projected under x- and y-polarized incidences when VO2 is metallic. Similarly, two additional holograms are achieved as VO2 is insulating. As a novel solution to terahertz multi-channel holography, this work may be applied to compact optical system and high-volume optical encryption.

Weighted Secrecy Sum Rate Optimization for Simultaneously Transmitting and Reflecting Reconfigurable Intelligent Surface-Assisted Multiple-Input Single-Output Systems

The study investigates the effectiveness of a novel Simultaneously Transmitting and Reflecting Reconfigurable Intelligent Surface (STAR-RIS) technology in enhancing the physical layer security of Multiple-Input Single-Output (MISO) systems. To address the complexity of the security challenge, we examine two distinct phase shift strategies, namely, the coupled phase scheme and the independent phase scheme. The coupled paradigm focuses on optimizing weighted sum secrecy rate (WSSR) through a customized Block Coordinate Descent (BCD) approach integrated with path tracking, aiming to achieve a balanced security enhancement. Furthermore, for the independent phase shift paradigm, an optimization algorithm based on the Concave–Convex Procedure (CCCP) is explored to provide a flexible security solution. The numerical results validate the superior performance of STAR-RIS, confirming its potential as a robust security enhancer for MISO systems.

A novel phase measuring deflectometry based on polar coordinate

Phase measuring deflectometry (PMD) is a method measure the surface of a mirror. However, when measuring convex mirrors, Cartesian coordinate fringes experience extreme compression. To address this issue, this paper proposes a novel PMD based on polar coordinate. This new method defines two linearly independent phase modulation directions, using the orthogonal basis of polar coordinate. It establishes polar coordinate fringes with rotational symmetry and radial pre-modulation, effectively reducing the impact of extreme compression at the edges. To correct the phase errors in polar coordinate fringes, a phase error compensation algorithm based on greyscale gradient is introduced. The algorithm calculates the influence factor of the eight connected domains around the error points to be compensated, utilising the phase grey gradient. The wavefront gradient data obtained through polar coordinate fringes are radial and tangential. Hence, a surface reconstruction method is proposed based on the Zernike partial derivative polynomial based on polar coordinate. In this method, the tangential partial derivatives and radial partial derivatives of the first 36 terms of Zernike in polar coordinate to construct Gram matrix equations. As a result, linearly independent Zernike recovery coefficients are obtained from coupled aliasing gradient data. Compared to the Cartesian coordinate system, the proposed method significantly reduces the fitting coefficient errors. Experimental measurements of convex mirrors with radii of curvature of 200 mm and 100 mm were conducted. The results demonstrate that compared to traditional PMD, this technique not only effectively suppresses extreme compression and increases the measurement area but also improves measurement accuracy by six times.

MBFT: A Modular Byzantine Fault Tolerance Protocol for high adaptability

With the substantial increase in permissioned blockchain applications, various application scenarios for Byzantine Fault Tolerance (BFT) protocols are emerging. However, due to the inherent complexity of BFT, the performance improvement of BFT protocols in one aspect generally comes at the expense of degradation in others. The contradiction between the diverse requirements and the inherent characteristics of BFT makes it challenging for traditional BFT protocols to effectively address the requirements of different scenarios in practice, and the rising number of protocols and implementations often overwhelm practitioners. To propose a solution to this dilemma and improve the adaptability and effectiveness of BFT protocols in different scenarios, a novel Modular Byzantine Fault Tolerance protocol (MBFT) has been proposed, whose core idea is to utilizes modular methods to quickly and flexibly construct satisfactory BFT protocols that meet the requirements of specific scenarios. MBFT deconstructs the single-layer leader-based BFT protocol into three independent phases and provides two typical modules with different characteristics for each phase. By combining different modules, BFT protocols with different characteristics and guarantee safety, liveness and even Byzantine democracy can be obtained. The safety, liveness and Byzantine democracy of MBFT are theoretically proved, the fault resistance capability of MBFT and the relationship between the level of cluster clock synchronization and Byzantine democracy are analyzed. Extensive experimental results highlight that MBFT has high adaptability and excellent performance compared with some state-of-the-art protocols.

Configurable dual-band inverted-E type phase shifter

In this paper, we propose dual-band phase shifters based on the Inverted-E topology, which can be configured for independent phase shift values at the two design frequencies. The simple structure comprises of a 50 Ω Main Transmission Line (MTL), whose electrical length is proportional to the frequency, loaded with three equally spaced open circuited stubs, which provide the required susceptance values at the two design frequencies. The required parameter values of the open circuited stubs are extracted using a Genetic Algorithm (GA). For validation, two prototype dual-band phase shifters with equal phase shifts of 45° and independent phase shifts of 45° and 90° at f 1 = 1 GHz and f 2 = 5.5 GHz are designed and developed. The measured results closely align with simulations, demonstrating that the proposed design achieves the required phase shifts at both frequencies with phase error less than 1° and insertion losses < 2 dB.

Phase separation of PML/RARα and BRD4 coassembled microspeckles governs transcriptional dysregulation in acute promyelocytic leukemia

In acute promyelocytic leukemia (APL), the promyelocytic leukemia-retinoic acid receptor alpha (PML/RARα) fusion protein destroys PML nuclear bodies (NBs), leading to the formation of microspeckles. However, our understanding, largely learned from morphological observations, lacks insight into the mechanisms behind PML/RARα-mediated microspeckle formation and its role in APL leukemogenesis. This study presents evidence uncovering liquid-liquid phase separation (LLPS) as a key mechanism in the formation of PML/RARα-mediated microspeckles. This process is facilitated by the intrinsically disordered region containing a large portion of PML and a smaller segment of RARα. We demonstrate the coassembly of bromodomain-containing protein 4 (BRD4) within PML/RARα-mediated condensates, differing from wild-type PML-formed NBs. In the absence of PML/RARα, PML NBs and BRD4 puncta exist as two independent phases, but the presence of PML/RARα disrupts PML NBs and redistributes PML and BRD4 into a distinct phase, forming PML/RARα-assembled microspeckles. Genome-wide profiling reveals a PML/RARα-induced BRD4 redistribution across the genome, with preferential binding to super-enhancers and broad-promoters (SEBPs). Mechanistically, BRD4 is recruited by PML/RARα into nuclear condensates, facilitating BRD4 chromatin binding to exert transcriptional activation essential for APL survival. Perturbing LLPS through chemical inhibition (1, 6-hexanediol) significantly reduces chromatin co-occupancy of PML/RARα and BRD4, attenuating their target gene activation. Finally, a series of experimental validations in primary APL patient samples confirm that PML/RARα forms microspeckles through condensates, recruits BRD4 to coassemble condensates, and co-occupies SEBP regions. Our findings elucidate the biophysical, pathological, and transcriptional dynamics of PML/RARα-assembled microspeckles, underscoring the importance of BRD4 in mediating transcriptional activation that enables PML/RARα to initiate APL.

Realization of spinful metaphotonic stokes skyrmions

Abstract Topologically protected skyrmion textures of light have garnered significant attention due to their potential applications in next-generation high-density data storage and logic devices. However, achieving compact and tunable on-chip skyrmion modes remains a formidable challenge. In this work, we present a novel approach empowered by birefringent metasurfaces to generate and manipulate spin-multiplexed photonic skyrmion textures. By encoding independent phase profiles onto orthogonal spin states, we observe the emergence of anti-skyrmions and skyrmioniums via Stokes parameter measurements, elucidating their distinct topological characteristics. This spin-multiplexed metasurface platform not only facilitates high-dimensional multiplexing but also enables the miniaturization of topological quasi-particles, offering promising prospects for applications in optical memory, information processing, and communications.

Reaching the efficiency limit of arbitrary polarization transformation with non-orthogonal metasurfaces

Polarization transformation is at the foundation of modern applications in photonics and quantum optics. Notwithstanding their applicative interests, basic theoretical and experimental efforts are still needed to exploit the full potential of polarization optics. Here, we reveal that the coherent superposition of two non-orthogonal eigen-states of Jones matrix can improve drastically the efficiency of arbitrary polarization transformation with respect to classical orthogonal polarization optics. By exploiting metasurface with stacking and twisted configuration, we have implemented a powerful configuration, termed “non-orthogonal metasurfaces”, and have experimentally demonstrated arbitrary input-output polarization modulation reaching nearly 100% transmission efficiency in a broadband and angle-insensitive manner. Additionally, we have proposed a routing methodology to project independent phase holograms with quadruplex circular polarization components. Our results outline a powerful paradigm to achieve extremely efficient polarization optics, and polarization multiplexing for communication and information encryption at microwave and optical frequencies.

Dual-Band Printed Near-Field Metasurface With Independent Phase Transformation for Enhanced Antenna Gain

Dual-Band Printed Near-Field Metasurface With Independent Phase Transformation for Enhanced Antenna Gain

Enhancing resilience: Integrating future flood modeling and socio-economic analysis in the face of climate change impacts

As climate change intensifies, future floods will become more severe in some areas with geographic variation, necessitating that local and regional governments implement systems to provide information for climate adaptation, particularly for vulnerable populations. Therefore, we aimed to develop a methodology to identify areas that are at an increased risk from future floods and independently socially vulnerable. In this study, 100-year recurrence interval flood extents and depths were estimated using an ensemble of six independent Coupled Model Intercomparison Project Phase 6 climate models for a past and future period under the highest-emissions climate scenario. The flood inundation results were related to social vulnerability for two selected study areas in the Mississippi River Basin. The range of flood extents and depths for both time periods were estimated, and differences were evaluated to determine the effects from climate change. To identify at-risk areas, the relationship between the spatial distribution of flood depths and vulnerability was then assessed. Finally, an analysis of the current and future damages on infrastructure from flooding on residential housing was performed to determine whether damages are correlated with higher vulnerability areas. Results show in every flooding scenario, flood extents and depths are increasing in the future compared with the past, ranging from an increase of 6 to 76 km2 in extent across both locations. A statistically significant relationship between spatial clusters of flooding and of vulnerability was found. The infrastructure analysis found that residential structures in the most vulnerable census tracts are 6 to 59 times more likely to experience moderate damage compared with the least vulnerable tracts depending on scenario. Overall, a framework was established to holistically understand the hydrologic and socioeconomic impacts of climate change, and a methodology was developed to use for allocating resources at the local scale.

Malfunctioning conformal phased array: Radiation pattern recovery with particle swarm optimisation

AbstractThe electronic beam steering in conformal phased arrays is formed by exciting the multiple antennas with appropriate phase shifts. However, the malfunctioning of phase shifters connected to the central antenna elements in the conformal array distorts the radiation pattern of the array system severely as compared to edge elements resulting in the reduction of the array gain and increase in the side lobe levels. Here, the authors propose a non‐dominated sorting multi‐objective particle swarm optimisation (NS‐MOPSO) technique capable of recalculating the independent phases of working antenna elements in the array in such a manner as to correct the overall radiation pattern. To illustrate the radiation pattern's recovery capabilities of the optimisation technique in case of malfunctioning of any random phase shifter(s), a 1 x 7 microstrip patch antenna array operating at 2.45 GHz on a wedge‐shaped conformal structure was designed in CST simulator. To test, the radiation pattern's recovery capabilities of the NS‐MOPSO approach, phase shifters connected to the antenna elements in the array were made to malfunction. Then the optimisation algorithm recalculates the phases for individual antenna elements to achieve the desired corrected radiation pattern. The simulated and measured radiation pattern recovery results are in good agreement with each other.

Simultaneous de novo calling and phasing of genetic variants at chromosome-scale using NanoStrand-seq

The successful accomplishment of the first telomere-to-telomere human genome assembly, T2T-CHM13, marked a milestone in achieving completeness of the human reference genome. The upcoming era of genome study will focus on fully phased diploid genome assembly, with an emphasis on genetic differences between individual haplotypes. Most existing sequencing approaches only achieved localized haplotype phasing and relied on additional pedigree information for further whole-chromosome scale phasing. The short-read-based Strand-seq method is able to directly phase single nucleotide polymorphisms (SNPs) at whole-chromosome scale but falls short when it comes to phasing structural variations (SVs). To shed light on this issue, we developed a Nanopore sequencing platform-based Strand-seq approach, which we named NanoStrand-seq. This method allowed for de novo SNP calling with high precision (99.52%) and acheived a superior phasing accuracy (0.02% Hamming error rate) at whole-chromosome scale, a level of performance comparable to Strand-seq for haplotype phasing of the GM12878 genome. Importantly, we demonstrated that NanoStrand-seq can efficiently resolve the MHC locus, a highly polymorphic genomic region. Moreover, NanoStrand-seq enabled independent direct calling and phasing of deletions and insertions at whole-chromosome level; when applied to long genomic regions of SNP homozygosity, it outperformed the strategy that combined Strand-seq with bulk long-read sequencing. Finally, we showed that, like Strand-seq, NanoStrand-seq was also applicable to primary cultured cells. Together, here we provided a novel methodology that enabled interrogation of a full spectrum of haplotype-resolved SNPs and SVs at whole-chromosome scale, with broad applications for species with diploid or even potentially polypoid genomes.

Exploring a Desirable Quadr-mRNAs Panel for Non-invasive and Ultrasensitive Bladder Cancer Diagnosis: In-silico and Clinical Studies.

Most patients with non-muscle invasive bladder cancer (NMIBC) have a high direction for recurrence and disease progression, which remains a significant unresolved challenge in bladder cancer patients. Therefore, a constant search is necessary for identifying appropriate and reliable biomarkers for early diagnosis of NMIBC. The current study has aimed to search for valuable diagnostic biomarkers in the tissue and urine specimens of NMIBC patients. The changes of twelve candidate mRNAs in a screening phase (40 tissue samples of NMIBC patients and their corresponding 40 urine specimens) and a subsequent independent validation phase (40 urine specimens) were estimated using real-time polymerase chain reaction (RT-qPCR). The receiver operating characteristic (ROC) analysis was executed to determine the potential diagnostic values of mRNAs. The mRNA levels of seven candidate genes were markedly higher in tissue specimens relative to their neighboring tissues. Among them, four mRNAs, including ERBB2, CCND1, MKI67, and MAGEA6, were differentially expressed in urine samples of NMIBC patients relative to control subjects. Further, the expression of these four mRNAs was validated in the validation step. Combining these biomarkers showed better diagnostic performance than single biomarkers in the urine sample for non-invasive NMIBC detection. The combination of these mRNAs and cytology enhanced the sensitivity of cytology from 37% to 87%. Our findings suggested that a four-mRNA panel may be promising in the non-invasive diagnosis of NMIBC, which deserves further investigation.

Design of High-Secure Digital/Optical Double Color Image Encryption Assisted by 9D Chaos and DnCNN

With the rapid development of multimedia technology, securing the transfer of images becomes an urgent matter. Therefore, designing a high-speed/secure system for color images is a real challenge. A nine-dimensional (9D) chaotic-based digital/optical encryption schem is proposed for double-color images in this paper. The scheme consists of cascaded digital and optical encryption parts. The nine chaotic sequences are grouped into three sets, where each set is responsible for encryption one of the RGB channels independently. One of them controls the fusion, XOR operation, and scrambling-based digital part. The other two sets are used for controlling the optical part by constructing two independent chaotic phase masks in the optical Fourier transforms domain. A denoising convolution neural network (DnCNN) is designed to enhance the robustness of the decrypted images against the Gaussian noise. The simulation results prove the robustness of the proposed scheme as the entropy factor reaches an average of 7.997 for the encrypted color lena-baboon images with an infinite peak signal-to-noise ratio (PSNR) for the decrypted images. The designed DnCNN operates efficiently with the proposed encryption scheme as it enhances the performance against the Gaussian noise, where the PSNR of the decrypted Lena image is enhanced from 27.01 dB to 32.56 dB after applying the DnCNN.

Polarization-multiplexing graphene-based coding metasurface for flexible terahertz wavefront control

In terahertz wireless communication systems, flexible wavefront control devices based on various structure metasurfaces have attracted enormous attention for next-generation communication. In general, tunable terahertz metasurfaces integrated with active materials or MEMS technologies are used for dynamic wavefront control. However, most existing metasurfaces suffer from various limitations, including intrinsic properties of active materials, low reliability of MEMS technologies, and single polarization mode of incident waves, which hinders their development and application. To address these challenges, herein, we design two types of reflective graphene-based coding metasurfaces for active wavefront control. The metasurface coding meta-atom is composed of a graphene split-ring resonator, a dielectric layer, and a metal ground plane. By simply rotating the coding meta-atom, independent 2π phase coverage for circularly polarized (CP) or linearly polarized (LP) illumination can be achieved, enabling polarization multiplexing. Thus, a metasurface (MS-1) is constructed based on the vortex phase profile to generate different wavefronts. Moreover, these wavefronts can be actively switched between a vortex beam, a multi-beam, and a specular reflection beam by altering the polarization mode of the incident waves and the Fermi level of the graphene coding regions Additionally, another metasurface (MS-2) is developed according to the parabolic phase profile to create a tunable metalens that allows active control over focal intensity and depth by adjusting the Fermi level of graphene. Such wavefront-controlled metasurfaces have high capacity and integration, making them very promising for potential applications in terahertz communication and imaging systems.

4-bit millimeter-wave Janus metasurface enabled polarization-spatial multiplexing holography.

Metasurface holography has become a surging and revolutionized field due to its flexible manipulation of amplitude and/or phase, which enhances the quality and capacity of holographic images. However, the current meta-holograms primarily focus on half-space manipulation, posing a challenge in developing simplified meta-hologram structures for spatial multiplexing. To address this situation, what we believe to be a novel 4-bit "Janus" metasurface combined with the weighted Gerchberg-Saxton (WGS) algorithm is proposed to record and reconstruct two distinct images in millimeter wave band. By meticulously designing the single-layer units, the 4-bit Janus metasurface achieves independent amplitude and phase responses in two orthogonal information channels. Moreover, the imaging ability of the proposed metasurface is investigated under different amplitude and phase dispersion. Comparative analysis also highlights several notable advantages of our work, including a low-profile design, polarization-frequency multiplexing, and enhanced imaging efficiency. The proposed method is verified through theoretical calculations, simulations, and experiments, and promises a versatile platform for applications in data storage, encryption, and auxiliary sensing.

Phase-Only-Induced Independent Full-Range Amplitude and Phase Manipulations Using Dual-Channel Transmitarrays

Phase-Only-Induced Independent Full-Range Amplitude and Phase Manipulations Using Dual-Channel Transmitarrays