Uniform Shell Research Articles

Hollow amorphous N-doped TiO2 microspheres with uniform shell thickness and high carrier separation efficiency for photocatalytic of high-concentration Cr(VI)

Due to the low quantum efficiency, pure N-doped TiO2 (NTO) is still ineffective for catalyzing high concentrations of pollutants. In this study, a novel hollow amorphous NTO photocatalyst (AH-NTO) was synthesized by ultrasonic-assisted hydrothermal method and applied to photocatalysis of high-concentration chromium-containing wastewater. The hollow structure was constructed using a three-dimensional Fe3O4 template, and the shell layer thickness changed regularly compared to the stirring method, suggesting that ultrasound contributes to the formation of a uniform shell. Meanwhile, the low crystallization kinetics induced by the ultrasound-assisted low-temperature hydrolysis process enhance the generation and stability of amorphous NTO. Characterization of the system demonstrated that the hollow amorphous structure improved visible-light utilization efficiency (∼70% light transmittance) and specific surface area (182.95 m2·g-1). Furthermore, the optimal photocatalyst exhibited a high photogenerated carrier signal (0.231 μA·cm-2), low interface resistance (374.8 Ω), and a strong oxygen vacancy signal (∼0.38 a.u.), which provides favorable conditions for the separation and transfer of photogenerated carriers. Based on these properties, the photocatalyst effectively treated wastewater containing 0.274 g·L-1 of Cr(VI). The removal efficiency decreased by only 0.18% over five consecutive cycles, demonstrating excellent cycle stability and activity. Therefore, this work provides a practical case for treating high-concentration pollutants.

Reduction in Heavy Rare Earth Diffusion Sources in Sintered Nd-Fe-B Magnets via Grain Boundary Diffusion of Dy70Ce70−xCu30

This study investigates the effect of Ce on the diffusion behavior of Dy-Cu alloys. The addition of Ce reduces the diffusion source melting point and promotes the formation of low-melting alloy phases, benefiting the diffusion behavior. The diffusion source with 10 wt.% of Ce shows the best magnetic performance, the coercivity of the magnet increases from 18.47 kOe to 23.60 kOe, and the incremental coercivity reaches 5.13 kOe. Ce diffusion improves the utilization of Dy, enhances diffusion uniformity, and promotes coercivity improvement. Ce also optimizes and regulates grain boundary phase structure distribution, consistent with magnetic property changes. Dy70Cu30 with an excessive thick shell layer wastes Dy and reduces utilization, while Dy60Ce10Cu30 has a relatively thin and uniform shell layer. Ce mainly distributes in the intergranular phase region, promoting Dy diffusion from the intergranular phase to form a shell layer. Excessive Ce can distort the magnet’s crystal structure, hindering magnetic property improvement. This study provides insights into optimizing the diffusion process and improving the Dy-Cu alloy.

Core Double-Shell FeCo@SiO2@PPy Nanocomposites for Tunable and Broadband Electromagnetic Wave Absorption

Electromagnetic wave absorption materials are essential for dealing with military stealth and electromagnetic pollution. However, challenges remain in regards to material stability and achieving broadband absorption. Constructing magnetic-dielectric core-shell structural composites with good morphology is one of the effective strategies to realize high-performance electromagnetic wave absorption. Herein, FeCo@SiO2@polypyrrole (PPy) core double-shell nanocomposite with uniform shell thicknesses is synthesized by environmentally friendly polyol method, sol-gel method and in-situ oxidative polymerization method. FeCo@SiO2@PPy nanocomposites with different PPy shell thicknesses were synthesized, and tunable electromagnetic wave absorption had been achieved. The reasonable combination of magnetic and dielectric components and the design of core double-shell structure optimized impedance matching and attenuation characteristics, resulting in strong and broadband electromagnetic wave absorption (minimum reflection loss: -62.7 dB, effective absorption bandwidth: 7.0 GHz). This work could initiate a new insight into the design and modulation of advanced electromagnetic wave absorption materials with strong and broadband absorption properties.

High-performance single SiC nanocable-based plasmonic photodetectors for ultraviolet communication systems

Silicon carbide (SiC) nanowires are the most promising candidate for developing high-performance single-nanowire-based UV photodetector (PD) with outstanding photoelectronic properties and low power consumption. However, SiC single-nanowire-based UV PDs commonly suffer from very low light current on the order of pA or nA, requiring precision equipment or an extra current amplification circuit, which greatly limit their practical application. To overcome this bottleneck, novel SiC single nanocable-based plasmonic PDs with the light current on the order of mA were successfully developed with the features of improving light absorption and reducing the dark current. The SiC/SiO2@Ag nanocables consisting of SiC nanowire core and uniform SiO2 shell encrusted with scattered and isolated Ag nanoparticles (NPs) were fabricated by a simple, low-cost, and space-confined vacuum-heating strategy using ultralong SiC nanowires and silver nitrate precursor followed by the annealing process. In such architecture, the in situ resulting SiO2 shell can effectively passivate the surface defects of the SiC nanowire core, restrain the photo-excited carrier's losses, and effectively block the hot electron injection, leading to a great reduction in the dark current and enhancement in the light current. The encrusted Ag NPs on the nanocable surface exhibited a strong LSPR effect with significantly increased optical absorption. Benefiting from the synergistic effect of SiO2 passivation and Ag nanoparticle LSPR effect, the device current increased dramatically by several orders of magnitude to reach 0.37 mA at a bias voltage of 3 V. Moreover, the developed SiC/SiO2@Ag PDs had faster response speed (0.27 s), lower dark current at the nA level, and high stability, which can be competent for the development of real-time, accurate, and cost-effective communication systems and flame detection with impressive switching ratio as high as 66012.

Transcriptome analyses of shell color and egg production traits between the uteruses of blue-green eggshell chickens and Hy-Line brown layers

Blue-green eggs exhibit unique shell color; however, compared to commercial layers, blue-green eggshell chickens have lower egg production and lack uniform shell colors. Aiming to confirm the molecular mechanisms that affect shell color and egg production, this study collected the uteruses of 12 blue-green eggshell chickens (BG group) and six Hy-Line layers (Brown group), which had significantly different shell color indexes (SCI) and egg numbers at 300 days of age (EN300). Transcriptome sequencing and comparative analyses were subsequently performed. BG hens were divided into two groups for comparative analysis (BGblue vs. BGgreen and BGlow vs. BGhigh, respectively), based on the differences in SCI and EN300, respectively. The result of weighted gene co-expression network (WGCNA) analysis showed that the sequenced and mapped 16,785 genes were clustered into 18 modules, among which six modules with a total of 4270 genes were highly correlated with SCI and EN300 traits. Five hundred and eleven differentially expressed genes (DEGs) belonged to the six key modules. Through KEGG mapping, GO enrichment, and Cytoscape network analysis, nine Hub genes were tightly associated with SCI and EN300. The up-regulated genes were CCR2, CCR8, CD40LG, IL18RAP, INHBA, and P2RY13, while the down-regulated genes were ABCA13, ADCY2, and GRM1. Co-analyses with the results of comparisons between the BG subgroups revealed that the expression of solute carrier (SLC) proteins and ABC transporters were highly related to eggshell color, while cytokine-cytokine receptor interactions and neuroactive ligand-receptor interactions were key pathways affecting egg production. The expression of extracellular cytokines and membrane receptors were significantly up-regulated in low-yield chickens. The candidate DEGs and pathways found in the study will assist in clarifying the molecular mechanisms affecting shell color and egg production, and improve the breeding of blue-green eggshell chickens.

Synthesis and characterization of Ni-based infiltration brazed coating reinforced with Co-P shell-coated WC

In this work the interface and wear resistance of Ni/WC infiltration-brazed cladding was increased by incorporating WC@Co-P reinforcements. This was achieved by depositing a Co-P nano-shell on the WC particles using the electroless plating technique. The morphology of the powders and the thickness of the Co-P shell were examined using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM), respectively. The phase compositions were analyzed through energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The results revealed that by optimizing the parameters of the electroless plating bath, a uniform Co-P shell with an average thickness of 80 nm was successfully deposited onto the WC particles. Through FESEM and EDS analyses, it was observed that the WC@Co-P/NiCrBSi coating exhibited higher compactness compared to conventional Ni/WC coating, along with a more homogeneous distribution of reinforcements. Additionally, unlike WC/NiCrBSi coating, no abnormal growth of particles occurred during molten phase sintering. Underpinning these findings are results from Pin-On-Disk tests which demonstrated notable improvements in various wear properties for the Co-P modified coating compared to conventional Ni/WC coating. Specifically, there was a 33 % increase in the coefficient of friction (0.3), a 40 % reduction in wear rate (0.006 g/Km), and a 26 % increase in hardness (1500 Vickers). These enhancements highlight the potential benefits offered by incorporating WC@Co-P reinforcements in improving interface quality and wear behavior for Ni/WC infiltration-brazed coating materials.

A Nonlinear Peptide Topology for Synthetic Virions.

a nonlinear de novo peptide topology for the assembly of synthetic virions is reported. The topology is a backbone cyclized amino-acid sequence in which polar l- and hydrophobic d-amino acid residues of the same-type alternate. This arrangement introduces pseudo C4 symmetries of side chains within the same cyclopeptide ring, allowing for the lateral propagation of cyclopeptides into networks with a [3/6, 4]-fold rotational symmetry closing into virus-like shells. A combination of computational and experimental approaches was used to establish that the topology forms morphologically uniform, nonaggregating and nontoxic nanoscale shells. These effectively encapsulate genetic cargo and promote its intracellular delivery and a target genetic response. The design introduces a nanotechnology inspired solution for engineering virus-like systems thereby expanding traditional molecular biology approaches used to create artificial biology to chemical space.

Highly capacitive MXene film by incorporating poly(3,4-ethylenedioxythiophene) hollow spheres prepared through an interfacial oxidation polymerization

Sheets stacking of Ti3C2Tx MXene dramatically reduces the ion-accessible sites and brings a sluggish reaction kinetics. While introducing transitional metal oxides or polymers in the MXene films could partially alleviate such issue, their enhanced performances are realized at the expense of electrode conductivity or cycling stability. Herein, we report an alternative spacer of conductive poly(3,4-ethylenedioxythiophene) (PEDOT) hollow spheres (HSs) which are fabricated by a facile template-assisted interfacial polymerization. The Fe3+ ions electrostatically adsorbed on the –SO3H groups of the sulfonated polystyrene spheres (S-PS) initiate the polymerization of uniform PEDOT shell, yielding uniform PEDOT HSs after dissolving the S-PS core. Introducing these PEDOT HSs in the MXene film generates the highly flexible MXene-PEDOT (MP) films featuring hierarchically porous network and high conductivity (283 S cm−1). Consequently, specific capacitance of 218 F g−1 at 3 mV s–1, along with a forty-folds decrease in relaxation time constant (1.0 vs 39.8 s) has been achieved. Moreover, the MP film also exhibits nearly thickness-independent capacitive performances with film thickness in the range of 10–46 μm. A maximal energy density of 21.2 μWh cm−2 at 1015 μW cm−2 together with 92 % capacitance retention over 5000 cycles are achieved for the MP-based solid-state supercapacitor. The intrinsic high conductivity, excellent mechanical flexibility and good structure integrity are responsible for such outstanding electrochemical behaviors.

Three-dimensional MoS2 nanosheets embeded within NiTe nanorods forming semicoherent heterojunctions achieving high-performance potassium-ion batteries

Three-dimensional MoS2 nanosheets uniformly embedded within NiTe nanorods are synthesized via one-step hydrothermal method and subsequently coated with a carbon layer to form stable NiTe@MoS2@C heterojunctions. The heterojunctions exhibit moderate lattice mismatch (δ =20.0 %), strong electric fields, and uniform carbon shells, resulting in unique electronic configurations and abundant active sites. As an anode for potassium-ion batteries, NiTe@MoS2@C demonstrated an high reversible capacity of 258.4 mAh g−1 after 100 cycles at a rate of 200 mA g−1. Moreover, it showed a stable reversible capacity of 177.5 mAh g−1 at a high rate of 5000 mA g−1, indicating excellent rate performance. Notably, even in the NiTe@MoS2@C//perylene tetracarboxylic dianhydride full battery configuration, a significant reversible capacity of 87.4 mAh g−1 was maintained after 100 cycles at a rate of 200 mA g−1, manifesting its remarkable potential for practical applications in potassium-ion batteries. Theoretical calculations further revealed that the well-designed NiTe@MoS2 heterojunction significantly enhances K+ ion diffusion.

Energetic properties of core–shell B@PVDF/AP composite micro-units prepared by electrostatic spraying technology

In this study, to improve the ignition and combustion performance of fuel boron (B) powder. The core–shell B@ polyvinylidene fluoride (PVDF)/ ammonium perchlorate (AP) composite micro-unit with the effect of erosion activation is successfully prepared by simple and controllable electrostatic spraying technology. The results of morphology and structural composition show that PVDF and AP are tightly wrapped on the surface of B, forming a uniform shell, which effectively prevents moisture absorption and oxidation of B during storage and transportation. The results of the thermal analysis show that the hydrofluoric acid (HF) gas generated by the decomposition of PVDF at about 100 °C in advance has a pre-ignition reaction (PIR) with the boron oxide (B2O3) film on the surface of B. The PIR generates boron fluoride (BF3) gas and breaks the B2O3 film. This reduces the initial oxidation temperature of B by 12.6 % and enhances the oxidation activity of B powder. In addition, the oxygen (O2) released by AP improves the combustion performance of B and strengthens the effect of erosion activation. It is also found that all samples can be successfully ignited and burned continuously, which improves the ignition and combustion performance of B powder. It is worth noting that the ignition delay time of the composite micro-unit sample with the stoichiometric ratio of B/PVDF/AP of 2: 1: 2 can be shortened to 0.454 s at most, which is 17 % lower than that of the physical mixed sample. Moreover, its combustion intensity and flame temperature also reach the best. These results show that the core–shell B@PVDF/AP composite micro-unit provides a great strategy for application in solid propellant and pyrotechnics.

Evaluation of quasi-static and dynamic compressive properties of Ti-6Al-4 V functionally graded shell lattices with minimal surfaces

Functionally graded shell (FGS) lattices have recently captivated enormous research interest in engineering applications for their outstanding mechanical and energy-absorbing performances. This paper designs FGS lattices featuring I-WP triply periodic minimal surfaces using implicit functions. FGS and uniform shell (US) samples made of Ti-6Al-4 V powder are manufactured utilizing laser powder bed fusion technology. Quasi-static compression and drop-weight impact experiments are conducted to evaluate the mechanical and energy-absorbing performances as well as deformation mechanism of FGS and US samples. The results demonstrate that the deformation modes of the samples under both loading conditions are similar, which is basically attributed to the drop-weight impact velocities being lower than the critical speeds calculated by the rigid-power-law hardening (RPLH) model. Additionally, the effects of loading velocity on the deformation mechanisms of US and FGS lattices are simulated, and homogenization, transition, and shock deformation models are predicted by the RPLH model. The FGS sample exhibits distinct layer-by-layer failures and eliminates the abrupt shear band under dynamic and quasi-static loadings. Compared to the quasi-static results, a notable strain rate hardening effect is observed under the dynamic condition, mainly due to the hardening of the row material. Consequently, the elastic modulus, yield strength, compression strength, and cumulative energy absorption of the US sample under drop-weight impact loading improved by 18.74 %, 56.52 %, 45.31 %, and 6.62 %, respectively. However, the FGS sample shows less sensitivity to strain rate owing to the layer-by-layer deformation mechanism, and their elastic modulus, yield strength, compression strength, and cumulative energy absorption only increased by 11.84 %, 34.72 %, 36.85 %, and 3.86 %, respectively. The FGS lattices exhibit a low peak stress during the compression process, which is favorable for industrial applications in crashworthiness and energy absorption.

Free and forced vibration analysis of uniform and stepped conical shell based on Jacobi-Ritz time domain semi-analytical method

Free and forced vibration analysis of uniform and stepped conical shell based on Jacobi-Ritz time domain semi-analytical method

Rational design of a setaria-like NiTe2/MoS2 semi-coherent heterogeneous interface for enhancing diffusion kinetics in potassium-ion batteries

Constructing unique heterostructures is a highly effective approach for enhancing the K+ storage capability of transition metal selenides. Such structures generate internal electric fields that significantly reduce the charge transfer activation energy. However, achieving a flawless interfacial region that maintains the optimal energy level gradient and degree of lattice matching remains a considerable challenge. In this study, we synthesised Setaria-like NiTe2/MoS2@C heterogeneous interfaces at which three-dimensional MoS2 nanosheets are evenly embedded in NiTe2 nanorods to form stabilised heterojunctions. The NiTe2/MoS2 heterojunctions display distinctive electronic configurations and several active sites owing to their low lattice misfits (δ = 13 %), strong electric fields, and uniform carbon shells. A NiTe2/MoS2@C anode in a potassium-ion battery (KIB) exhibited an impressive reversible capacity of 125.8 mAh/g after 1000 cycles at a rate of 500 mA g−1 and a stable reversible capacity of 111.7 mAh/g even after 3000 cycles at 1000 mA g−1. Even the NiTe2/MoS2@C//perylene tetracarboxylic dianhydride full battery configuration maintained a significant reversible capacity of 92.4 mAh/g after 100 cycles at 200 mA g−1, highlighting its considerable potential for application in KIBs. Calculations further revealed that the well-designed NiTe2/MoS2 heterojunction significantly promotes K+ ion diffusion.

Are monodisperse phospholipid-coated microbubbles “mono-acoustic?”

Phospholipid-coated microbubbles with a uniform acoustic response are a promising avenue for functional ultrasound sensing. A uniform acoustic response requires both a monodisperse size distribution and uniform viscoelastic shell properties. Monodisperse microbubbles can be produced in a microfluidic flow focusing device. Here, we investigate whether such monodisperse microbubbles have uniform viscoelastic shell properties and thereby a uniform “mono-acoustic” response. To this end, we visualized phase separation of the DSPC and DPPE-PEG5000 lipid shell components and measured the resonance curves of nearly 2000 single and freely floating microbubbles using a high-frequency acoustic scattering technique. The results demonstrate inhomogeneous phase-separated shell microdomains across the monodisperse bubble population, which may explain the measured inhomogeneous viscoelastic shell properties. The shell viscosity varied over an order of magnitude and the resonance frequency by a factor of two indicating both a variation in shell elasticity and in initial surface tension despite the relatively narrow size distribution.

Enhanced security through dye-doped cholesteric liquid crystal shells for anti-counterfeiting

We explored the application of fluorescent dye doped Cholesteric Liquid Crystal (CLC) shells for anti-counterfeiting measures. These shells exhibit unique optical properties and, when infused with a fluorescent dye, produce a distinct fluorescent color upon exposure to UV light. We developed a microfluidic device using glass capillaries to generate uniform CLC shells. The shells were analyzed using a Polarizing Optical Microscope (POM) to study their defect structures. For anti-counterfeiting, QR code was encoded with CLC shells that were photopolymerized under ultraviolet light for enhanced durability. In daylight, the code reflects red and blue colors, but under UV light, it reveals the fluorescent dye color. This QR code can only be decrypted with UV illumination in both red and blue CLC shells. The color changes are easily visible to the naked eye, making this technique suitable for immediate verification. By utilizing this straightforward technique, security and chromic-based applications can be implemented with significantly increased cost-effectiveness and efficiency, surpassing the results of traditional approaches.

Histodiagnosis of heterakidosis in chickens

The purpose of the research is to study pathology findings in heterakidosis in broilers.Materials and methods. The study used pathological material (cecum, liver) from 8 laying hens aged one year. Organ samples were delivered to the Pathology Sector in 10% buffered formalin. They were fixed for 36 hours and examined histologically using paraffin embedding. Semi-automatic Thermo Scientific equipment was used to process tissue samples. Histologic specimens were stained with hematoxylin and eosin. The specimen histoarchitecture was assessed with an Axio A1.0 microscope; photographs were taken using the AxioVision software.Results and discussion. Visual assessment of the pathological material revealed thickening of the distal cecum while the liver samples had no signs of pathology. It was found that Heterakis spp. was about 1 cm long; helminth eggs were oval-shaped and had a strong, uniform shell; their size was 49 × 26 micrometers in the mean. When dwelling in the cecum, Heterakis spp. causes atony of the distal cecum wall, and development of inflammatory and necrotic processes in the intestinal mucosa, which promotes active growth of bacterial flora, accumulation of bacterial byproducts and intoxication. In places where the helminth is localized, eggs accumulate and a risk of Histomonas spp. infection increases, namely, amoebic (in the intestinal lumen) and spherical (in the intestinal mucosa) forms of the protozoan were identified. It was not possible to differentiate Histomonas spp. in assessing the histological specimens of the liver from the infected birds. In diagnostics, we should consider the great similarity of morphological characteristics of Heterakis spp. and Ascaridia spp. eggs.

Efficient Ionic Conductor Anode Materials with Heterojunction Structure of MnOx/Si@C Utilized in Lithium‐Ion Batteries

AbstractThe rapid development of alternative energy vehicles has raised higher requirements for electrode materials. Silicon, with superhigh specific capacity, is highly anticipated in the field of lithium‐ion batteries (LIBs). Unfortunately, the original drawbacks of serious volumetric effect and poor conductivity have confined its commercial steps severely. Herein, a novel composite, based on submicron silicon flakes embedded into carbon shell, with heterojunction‐bearing MnOx nanoparticles, is designed and synthesized successfully via sanding process and in situ thermal reduction methods. The results of electrochemical performance tests and related fitting data show that the presence of MnOx particles facilitates rapid Li+ transport and reduces the impedance associated with Li+ diffusion from the surface to the inner core of the MnOx/Si@C material. The two‐dimensional (2D) silicon flakes and uniform carbon shell have positive influence on structural stability and electronic conductivity. Benefit from the rational design, the optimized MnOx/Si@C composite delivers an outstanding cycling stability of 1106.59 mAh·g−1 at 1 A·g−1 over 1000 cycles with a capacity retention of 71.09%. Besides, the goal material possesses a lithium‐ion diffusion coefficient of ≈1.04×10−9 cm2·s−1. This work provides a reference for the mass preparation of advanced anode materials for lithium‐ion batteries.

Preparation of functionalizable poly(propylene–styrene)/polyacrylonitrile millimeter‐scale particles with core‐shell morphology

AbstractCore‐Shell (CS) polymeric particles have attracted great interest due to their high mechanical, thermal, and chemical stability and their surface properties. In this study, functionalizable CS poly(propylene/styrene)/poly(acrylonitrile) (PP/PS/PAN) particles were prepared through heterogeneous polymerizations in a batch reactor. Commercial PP particles and PP/PS particles (prepared by seeded suspension polymerization of styrene (Sty) on PP spheres) were applied as core components of the final structure, while the shell was prepared through acrylonitrile dispersion polymerization. The degree of swelling of the core particles by Sty played an important role for the adhesion of the PAN shell, which for PP particles was 24 wt%, whereas for PP/PS hybrid particles it was 57 wt%. The particles (PP/PS and CS) were characterized through image analysis, revealing a uniform and smooth surface for PP/PS spheres and a uniform porous shell for CS particles. Particle size distributions, thermal degradation, chemical structures, degrees of crystallinity, and textural properties were also evaluated. The PAN shell adhered to the PP/PS particles without forming a copolymer, and the CS particles formed by a PP/PS core and PAN shell had sizes of 4.54 ± 1.24 mm, specific area of 2.70 m2g−1 and PAN content of 15.98 ± 0.82% (m/m) of total particles.

A tailored dual core-shell magnetic SERS substrate with precise shell-thickness control for trace organophosphorus pesticides residues detection

For addressing the challenges of strong affinity SERS substrate to organophosphorus pesticides (OPs), herein, a rapid water-assisted layer-by-layer heteronuclear growth method was investigated to grow uniform UiO-66 shell with controllable thickness outside the magnetic core and provide abundant defect sites for OPs adsorption. By further assembling the tailored Au@Ag, a highly sensitive SERS substrate Fe3O4-COOH@UiO-66/Au@Ag (FCUAA) was synthesized with a SERS enhancement factor of 2.11 × 107. The substrate's suitability for the actual vegetable samples (cowpeas and peppers) was confirmed under both destructive and non-destructive detection conditions, showing a strong SERS response to fenthion and triazophos, with limits of detection of 1.21 × 10-5 and 2.96 × 10-3 mg/kg in the vegetables under destructive conditions, and 0.13 and 1.39 ng/cm2 for non-destructive detection, respectively. The FCUAA substrate had high SERS performance, effective adsorption capability for OPs, and demonstrated good applicability, thus exhibiting great potential for rapid detection of trace OPs residues in the food industry.

Towards high-performance polarimeters with large-area uniform chiral shells: a comparative study on the polarization detection precision enabled by the Mueller matrix and deep learning algorithm

Polarization detection and imaging technologies have attracted significant attention for their extensive applications in remote sensing, biological diagnosis, and beyond. However, previously reported polarimeters heavily relied on polarization-sensitive materials and pre- established mapping relationships between the Stokes parameters and detected light intensities. This dependence, along with fabrication and detection errors, severely constrain the working waveband and detection precision. In this work, we demonstrated a highly precise, stable, and broadband full-Stokes polarimeter based on large-area uniform chiral shells and a post-established mapping relationship. By precisely controlling the geometry through the deposition of Ag on a large-area microsphere monolayer with a uniform lattice, the optical chirality and anisotropy of chiral shells can reach about 0.15 (circular dichroism, CD) and 1.7, respectively. The post-established mapping relationship between the Stokes parameters and detected light intensities is established through training a deep learning algorithm (DLA) or fitting the derived mapping-relationship formula based on the Mueller matrix theory with a large dataset collected from our home-built polarization system. For the detection precision with DLA, the mean squared errors (MSEs) at 710 nm can reach 0.10% (S1), 0.41% (S2), and 0.24% (S3), while for the Mueller matrix theory, the corresponding values are 0.14% (S1), 0.46% (S2), and 0.48% (S3). The in-depth comparative studies indicate that the DLA outperforms the Mueller matrix theory in terms of detection precision and robustness, especially for weak illumination, small optical anisotropy and chirality. The averaged MSEs over a broad waveband ranging from 500 nm to 750 nm are 0.16% (S1), 0.46% (S2), and 0.61% (S3), which are significantly smaller than those derived from the Mueller matrix theory (0.45% (S1), 1% (S2), and 39.8% (S3)). The optical properties of chiral shells, the theory and DLA enabled mapping-relationships, the combination modes of chiral shells, and the MSE spectra have been systematically investigated.