Electric Field Intensity Distribution Research Articles

Electromagnetic field simulation modeling method and distribution characteristics of electric vehicle wireless charging system

In recent years, wireless charging technology for electric vehicles has gained significant attention. To accurately analyze the distribution characteristics of the electromagnetic field during the wireless charging process of electric vehicles, a finite element-based electromagnetic analysis method was employed. Applied in the commercial simulation software, the electromagnetic environment of the resonant coil and electric vehicle model was simulated under high-power charging conditions, resulting in an overall electromagnetic field distribution for the electric vehicle. The results indicated that within the coil region, the magnetic induction intensity in the central area of the coil was zero, and it increased as the distance from the center of the coil grew. Outside the coil region, the magnetic induction intensity gradually decreased. The electric field intensity of the resonant coil was maximum in the central area of the coil, and it weakened as the distance from the center of the coil increased. When a magnetic shielding resonant coil was used, the electromagnetic field was confined between the shielding materials, and the magnetic field rapidly attenuated on both sides of the magnetic shield. The electromagnetic field energy of the electric vehicle body was mainly concentrated at the bottom of the vehicle near the coil. When the coil was located in the front of the car body, the maximum electric field intensity distribution in the car body was 8.50 V/m, and the maximum magnetic induction intensity was 0.024 μT. When the coil was located in the middle of the car body, the maximum electric field intensity was 2.31 V/m, the maximum magnetic induction intensity was 0.019 μT. As the distance from the coil position increased, the energy weakened.

Dual-functional Au-porous anodic alumina (PAA) sensors for enrichment and label-free detection of airborne virus with surface-enhanced Raman scattering

The development of a rapid and sensitive method for the enrichment and direct detection of airborne viruses has become urgently needed to prevent their spread. We have developed a dual-functional, label-free platform for the enrichment and optical identification of airborne viruses. This platform allows for the on-site enrichment and identification of airborne viruses through a virus enrichment component combined with surface-enhanced Raman scattering (SERS). In this work, we created an Au-porous anodic alumina (PAA) composite film, by ion sputtering Au nanoparticles (Au NPs) on a porous structure. The Au-PAA serves as a dual-functional sensor: it combines ultrafiltration through the vertical nanopores in the PAA for virus enrichment and constitutes a plasmonic substrate due to the surface plasmon near-field enhancements within the nanochannel structure. This sensor demonstrates an extraordinary enrichment efficiency (about 98 %) of obtained bioaerosols and enables simultaneous, sensitive detection at the single-virus level. Finite-difference time-domain (FDTD) simulations evidenced the electric field intensity and charge distribution of the Au-PAA. This Au-PAA composite film offers a powerful system for on-site, label-free viral particle enrichment and SERS detection. Contaminated air containing viruses can be collected in a few minutes and analyzed immediately by our platform, which is particularly beneficial for timely monitoring of viruses in the air of large public spaces. Additionally, this platform can be applied to evaluate the indoor air quality.

The experimental and theoretical study on the spatial‐temporal distribution of electromagnetic radiation from JO‐8 explosions.

AbstractThe detonating fuse in the multistage warhead will be subjected to strong electromagnetic interference, derived from electromagnetic radiation generated by explosion of the shaped charge warhead, which may cause premature detonation or misfire. In order to explore the possible electromagnetic environment surrounded the detonating fuse, the spatial‐temporal distribution of electromagnetic radiation after the explosion of JO‐8 explosive was investigated in this paper. The electromagnetic radiation signal was collected and its frequency coverage was analyzed in the far‐field area by the field blast test. Moreover, based on electromagnetic theory, a theoretical model of electromagnetic radiation generated by the explosion of JO‐8 explosive was established, and the spatial‐temporal distribution of the electric field intensity was illustrated in detail for several typical positions after the explosion. The better agreement between experimental and theoretical results indicates that the proposed theoretical model and computational method are reasonable. On this basis, the distributions of electric field intensity for different positions and various explosive weights were predicted respectively by using distance and explosive weight as variables. This study is expected to provide a reference for the research on the electromagnetic radiation for explosive explosion and anti‐explosive electromagnetic interference.

Dual-band topological rainbows in Penrose-triangle photonic crystals.

Topological rainbows (TRs) possess the potential to separate and localize topological photonic states across different frequencies. However, previous works on TRs have been confined to a single-frequency band. Furthermore, the achievement of multiband TRs within a single structure is still a significant challenge. In this paper, a composed structure waveguide is designed based on Penrose-triangle photonic crystals. By adjusting the size of scatterers and introducing non-Hermitian terms, we successfully realize dual-band TRs. This achievement will not only enhance the uniformity of the electric field intensity distribution but also provide the potential to introduce a new avenue for the development of robust photonic devices dedicated to processing vast amounts of data information.

Enhancement and Broadening of the Internal Electric Field of Hole-Transport-Layer-Free Perovskite Solar Cells by Quantum Dot Interface Modification.

Hole-transport-layer-free perovskite solar cells have attracted strong interest due to their simple structure and low cost, but charge recombination is serious. Built-in electric field engineering is an intrinsic driver to facilitate charge separation transport and improve the efficiency of photovoltaic devices. However, the enhancement of the built-in electric field strength is often accompanied by the narrowing of the space charge region, which becomes a key constraint to the performance improvement of the device. Here, we propose an effective regulation method, the component engineering of quantum dots, to enhance the strength of the built-in electric field and broaden the range of space charge. By using all inorganic CsPbBrxI3-x (x = 0, 1, 2, 3) quantum dot interface modification to passivate the defects of MAPbI3 perovskite films, the regulation law of quantum dot components on the work function of perovskite films was revealed, and the mechanism of their influence on the internal electric field intensity and space charge region distribution was further clarified, thereby fundamentally solving the serious problem of charge recombination. As directly observed by electron-beam-induced current (EBIC), the introduction of CsPbBr2I quantum dots can effectively enhance the interfacial electric field intensity, widening the space charge region from 160 to 430 nm. Moreover, the efficiency of the hole-free transport layer perovskite solar cells modified by CsPbBr2I quantum dots was also significantly enhanced by 1.5 times. This is an important guideline for electric field modulation and efficiency improvement within photovoltaic devices with other simplified structures.

Rotationally displaced electric field intensity distribution around square nanoantennas induced by circularly polarized light

Rotationally displaced electric field intensity distribution around square nanoantennas induced by circularly polarized light

Tunable acoustic graphene plasmon enhanced nano-infrared spectroscopy

Nano-infrared spectroscopy (nano-IR) technology can surpass the diffraction limit of light, achieving infrared spectroscopic detection with a spatial resolution of ~ 10 nm, which is an important technical means for studying the chemical composition and structure of molecules at the nanoscale. However, the weak infrared absorption signals of nanoscale materials pose a significant challenge due to the large mismatch between their dimensions and the wavelength of infrared light. The infrared absorption signals of molecular vibrational modes are proportional to the square of the electromagnetic field intensity at their location, meaning that higher electromagnetic field intensity can significantly enhance molecular detection sensitivity. Acoustic graphene plasmons (AGP), excited by the interaction between free charges in graphene and image charges in metals, exhibit strong optical field localization and electromagnetic field enhancement. These properties make AGP an effective platform for enhancing nano-IR detection sensitivity. However, the fabrication of graphene nanostructures often introduces numerous edge defects due to the limitations of nanofabrication techniques, significantly reducing the electromagnetic field enhancement observed in experiments. Here, using finite element simulation, we theoretically propose a tunable enhanced nano-IR detection platform based on nanocavity-acoustic graphene plasmon (n-AGP), utilizing a graphene/air gap/gold nanocavity structure. This platform avoids the need for nanofabrication of graphene, thereby preventing defects and contamination introduced by processes such as electron beam exposure and plasma etching. By plotting the dispersion of n-AGP, we found that n-AGP has a high wavelength compression capability comparable to AGP (<i>λ</i><sub>0</sub>/<i>λ</i><sub>AGP</sub> = 48). Additionally, due to the introduction of the gold nanocavity structure, n-AGP possess an extremely small mode volume (<i>V</i><sub>n-AGP</sub> ≈ 10<sup>-7</sup><i>λ</i><sub>0</sub><sup>3</sup>, <i>λ</i><sub>0</sub> = 6.25 μm). By calculating the electric field intensity distribution (|<i>E</i><sub>norm</sub>|) and the normalized electric field intensity spectrum (i.e., the relationship between frequency and (|<i>E</i><sub>z</sub>|/|<i>E</i><sub>0</sub>|) of the n-AGP structure, it is evident that due to the high electron density on the gold surface, electromagnetic waves can reflect at the boundaries of the gold nanocavity and be resonantly enhanced within the nanocavity. At the resonant frequency of n-AGP (1800 cm<sup>-1</sup>), the electric field enhancement within the cavity is about 50 times. In contrast, at similar resonant frequencies, the electric field enhancement factors of Graphene plasmon (resonant frequency 1770 cm<sup>-1</sup>) and AGP (resonant frequency 1843 cm<sup>-1</sup>) are approximately 3 and 2 times, respectively, significantly lower than that of n-AGP. Furthermore, by placing a protein film (60 nm wide and 10 nm high) under the graphene, we calculated the spectral dip depths caused by Fano resonance between n-AGP and AGP with the vibrational modes of protein molecules, thereby validating the enhancement factors of different modes for protein vibrational mode infrared absorption. For the amide I band of proteins, the detection sensitivity of n-AGP is about 60 times higher than that of AGP. Additionally, we discovered that by adjusting the structural parameters of the gold nanocavity, including cavity depth, width, and surface roughness, the response frequency band of n-AGP can be modulated (from 1290 to 2124 cm<sup>-1</sup>). Specifically, as the cavity depth increases, the electric field enhancement of n-AGP improves, and the wavelength compression capability of n-AGP decreases, causing the resonant frequency to blue-shift (from 1793 cm<sup>-1</sup> to 2124 cm<sup>-1</sup>). As the cavity width increases, the resonant frequency of n-AGP red-shift (from 1793 cm<sup>-1</sup> to 1290 cm<sup>-1</sup>), and the effectiveness of the gold nanocavity boundary in reflecting the resonant electric field within the cavity diminishes, resulting in a decrease in the electric field enhancement factor. With the gradual increase in the roughness of the gold nanocavity bottom, the effective depth of the gold nanocavity increases, causing a blue shift in the n-AGP resonant frequency (from 1793 cm-1 to 1861 cm<sup>-1</sup>) and an increase in the electric field enhancement factor. Moreover, by adjusting the Fermi level of graphene (from 0.3 eV to 0.6 eV), we achieved dynamic tuning of n-AGP (from 1355 to 1973 cm<sup>-1</sup>). As the Fermi level of graphene increases, the wavelength compression capability of n-AGP decreases, resulting in a blue-shift in the resonant frequency. Finally, by optimizing the structural parameters and Fermi level of n-AGP, and placing protein particles of different sizes (20 nm, 15 nm, and 10 nm wide, all 10 nm high) into the graphene/gold nanocavity structure, we verified the protein detection capability of n-AGP-enhanced nano-IR. We found that n-AGP can detect the vibrational fingerprint features of the amide I and amide II bands of a single protein particle (10×10 nm) with a 15-fold increase in sensitivity. This n-AGP-based enhanced structure holds promise for providing an important detection platform for nanoscale material characterization and single-molecule detection, with broad application potential in biomedicine, materials science, and geology.

High entropy alloy cladding on mild steel substrate using microwave energy at 2.45 GHz: An insight from multi-physics simulation study to experimental investigations

Microwave hybrid heating (MHH) has emerged as a novel technology for cladding high-entropy alloy (HEA) powders on metallic substrates. The existence of a multi-material system (Al, Co, Cr, Ni, and Ti powder) in HEA provides difficulties in microwave cladding. These problems are addressed in the current study by employing silicon carbide as a susceptor material for MHH to microwave-clad AlCoCrNiTi HEA on a mild steel substrate. A multi-physics model of the microwave cladding setup was constructed to investigate the cladding properties. The model was verified using experimental data, and simulation was used to examine the electric field, resistive losses, energy distributions, and temperature-time profile. The simulation results indicated that the electric field intensity, resistive losses, and energy distribution were at their maximum near the susceptor and the cladded surface. As a result, the HEA-cladded surface reached a temperature of 1030 °C at the central plane. This is comparable to the experimental temperature of 1041 °C in 41 min, which shows an error of <10 %. From the microstructural investigation, the HEA powder exhibited a flaky microstructure and a uniform distribution of all the constituents, resulting in a solid metallurgical link between the HEA powder and substrate. The surface hardness of mild steel components was enhanced intensely by three times with the inclusion of AlCoCrNiTi HEA cladding.

Induced electric field intensity-enhancing water-drop triboelectric nanogenerator

Triboelectric nanogenerators (TENGs) can collect energy from the surrounding environment to provide energy for small electrical equipment and sensors. Water drop triboelectric nanogenerators (WD-TENGs) are useful for harvesting clean energy from raindrops, but the commonly used structure of WD-TENGs for water drop energy harvesting has a poor induced charge quantity. Here, we analyze the electric field intensity distribution closing the triboelectric layer when a water droplets induced charges. The amount of droplet-induced charge was increased by regulating the electric field intensity distribution. Thus, an induced charge-enhanced WD-TENG structure was designed to increase the open-circuit voltage and short-circuit current of the TENG by about 4 times. This improved the output performance of the TENG. The working principle and structure of the designed WD-TENG can help optimize the performance of other TENGs.

Manipulation of plasmonic vortex fields using positive elliptically polarized beams

Several studies have investigated methods for the direct excitation of surface plasmon polariton (SPP) vortex fields by using scalar beams with linear and circular polarization. In this paper, we propose novel devices for generating SPP vortex fields by using positive elliptically polarized beams. These devices excited SPP vortices with a uniform electric field intensity distribution, that did not vary arbitrarily with changes in the incident beam amplitude ratio. Moreover, when the incident scalar beam was transformed into a vector beam with different amplitude ratios at every point in space, the topological charge of the SPP vortex field could be dynamically modulated by changing the polarization order and rotation direction of the incident vector beam. The fields generated by different structures after the superposition of SPP vortices had spatial intensity distributions that varied with changes in the incident beam amplitude ratio. These properties provide a new idea for realizing different spatial intensity distributions for a dynamic modulation SPP field.

The Effect of Body Mass Index on Tumor Treating Fields (TTFields) Intensity Distribution in the Lungs

Tumor Treating Fields (TTFields) therapy is a locoregional, noninvasive antimitotic cancer treatment modality. TTFields are electric fields that disrupt processes critical for cancer cell viability and tumor progression. They are generated by a portable medical device and delivered noninvasively to the tumor via two pairs of orthogonally placed transducer arrays. TTFields therapy is currently FDA-approved for recurrent and newly diagnosed glioblastoma and pleural mesothelioma, with ongoing studies in other solid tumor types including non-small cell lung cancer (NSCLC). In the phase 3 LUNAR study (NCT02973789), TTFields therapy demonstrated an improvement in overall survival when added to NSCLC standard of care. TTFields effectiveness depends upon several factors, including field intensity; thus, it is relevant to assess the impact of body mass index (BMI) on the distribution of TTFields in the lungs. This study utilized simulation-based approaches to assess the impact of BMI on electric field intensity distribution in the lungs. Three computerized female phantom models (with BMIs of 22, 26 and 30), were used to simulate electric field intensity. Two different arrays sizes (small [13 disks] and large [20 disks]) were applied to the thoracic region of the models. An electric field intensity distribution map for each model was generated, and electric field intensity values across the entirety of the lungs were analyzed. Electric field intensities were above 1 V/cm (amplitude), which is typically considered a sufficient level of TTFields dose to achieve a therapeutic effect, in all lobes in the lungs for all BMI models when large arrays were used. Therapeutic intensities were achieved in all lobes with the small arrays in all but one model (BMI 30), where intensities fell slightly below 1 V/cm in the right middle lobe. Results from this simulation-based study demonstrate that delivery of TTFields at therapeutic intensities is feasible even in patients with a high BMI, provided the appropriately sized array is used. These findings support ongoing clinical studies of TTFields therapy in lung cancer, including the recently completed LUNAR study in advanced NSCLC, and could facilitate optimization of therapeutic TTFields delivery to individual patients, based on their BMI.

Theoretical simulated fabrication of nanostructure by interference of four-beam guided mode excited by 193 nm laser

This study proposed a lithography method for fabricating periodic nanostructures using the interference of four-beam TE0 guided modes excited by a 193 nm deep ultraviolet laser. The physical mechanism and normalized electric field intensity distribution of four-beam TE0 guided mode interference were theoretically analyzed and numerically simulated using the finite element method. The simulation results confirmed the ability of this method to fabricate periodic structures with a half-pitch resolution of 30.35 nm (approximately λ/6.36), an aspect ratio of 3.95, and a contrast ratio of 1. The theoretically calculated value of the resolution was consistent with the numerical simulation value. The resolution and aspect ratio of the fabricated nanostructures could be adjusted through changes to the thickness of the resist. Moreover, the shape of the fabricated nanostructures, such as the one-dimensional sub-wavelength grating structure and two-dimensional square array lattice structure, were adjustable via changes to the number and azimuth of the excited TE0 guided modes. The results obtained in this study provide valuable theoretical information for the practical manufacture of ultra-high-resolution lithography.

畜禽舍空间相控分裂导线复合除尘杀菌装置设计研究

Livestock scale breeding is the inevitable trend of future livestock and poultry husbandry. Closed breeding requires excellent environment and livestock and poultry housings contain a lot of dust, pathogenic microorganisms and harmful gases, affecting the health of livestock and poultry and breeding personnel. Most of the common sterilization and dust collection devices for livestock and poultry housings on the market are too high energy consumption, and easy to cause secondary pollution. Therefore, an environmental purification device was designed to absorb dust in the air and kill harmful bacteria by using high voltage pulsed electric field. The device was designed using phase control principle and bundled conductor. COMSOL Multiphysics software was used to simulate the layout of single conductor, twin bundled conductor and quad bundled conductor. It was found that when the conductor was designed as twin bundled conductor or quad bundled conductor, the gradient distribution of spatial electric field intensity was more uniform and the downward trend of electric field was slower, which could effectively improve the dust collection and sterilization efficiency of the device. At the same time, a variety of electric field environments can be set up by using phase difference to meet different environmental requirements of livestock and poultry. The compound dust collection and sterilization device with phase-controlled bundled conductor for livestock and poultry housing space includes high voltage pulse generator, bundled conductor, high voltage special timer, insulator and other parts, which can effectively reduce the dust content in the air, the concentration of pathogenic bacteria, harmful gases, etc. after assembly test and can also reduce the humidity in the livestock and poultry housings.

Research on depth control of machining trace in electrochemical trepanning

Electrochemical trepanning (ECTr) is a highly effective and economic manufacturing technology for machining difficult-to-cut metal materials that are often used in aeroengine components. Integral structural components such as blisks, diffusers, etc. are composed of hubs and blades. In continuous ECTr, machining trace stems from on the hub between adjacent blades. The depth of machining trace significantly influences the surface integrity of the integrated components, even causes the scrapping of the workpiece. In order to solve the problem of machining trace in ECTr, a cathode design method based on the relation between cathode profile and electric field distribution is proposed in this study, the edge of the cathode that affects the machining trace is chamfered. A electric field model of ECTr is established and dynamic electric field simulation of ECTr for cathodes with different chamfered edges is performed. The electric field intensity distribution at the cathode edge and the forming profile of the hub are compared. The simulation results show that optimal chamfering parameters can improve the machining trace. Subsequently, a group of cathodes with different chamfered edge is designed, and corresponding ECTr experiments are conducted. The optimal chamfering parameters are determined (α = 5°, b = 2 mm), the depth of the machining trace is reduced from 0.370 mm to 0.122 mm, the surface flatness is significantly improved. Overall, this depth control method of machining trace is verified effectively.

Size modulation of plasmonic In2O3 nanocube optimized photocatalytic H2 evolution over stack g–C3N4–In2O3 heterojunction

A strategy of tuning the size of In2O3 nanocube was employed to change the surface property of g–C3N4–In2O3 heterojunction to boost its photocatalytic H2 production. In the type II g–C3N4–In2O3 heterojunction, the change on the size of In2O3 nanocube (30, 60 and 120 nm) could regulate visible light utilization ability and photoelectric conversion efficiency of photogenerated charge carriers. The directional transfer of charge carriers caused the accumulation of photoexcited electron in plasmonic In2O3 and localized electric field enhancement. The intensity and spatial distribution of localized electric field could be tuned by the adjustable size of In2O3 nanocube. Therefore, the obtained g–C3N4–In2O3 heterojunction with an optimal size of In2O3 nanocube (60 nm) exhibited supreme photocatalytic H2 evolution rate of 3.1 mmol h−1 g−1 with a high apparent quantum efficiency of 5.27%, which was 7.5 times higher than that of bare g-C3N4 nanosheet (0.4 mmol h−1 g−1).

Electric field distribution and performance optimization of high-speed train cable terminal with internal defects

High voltage cable terminal of high-speed electric multiple units (EMU) is an important part of on-board high voltage equipment. As the weak link of the cable assembly, the cable terminal is prone to penetrability discharge and resulting in insulation failure, which seriously affects the EMU’s safety and reliability. The electric field intensity distribution of high-voltage cable terminal with internal defects such as air gaps, moisture, semiconductors and carbons are simulated and studied. At the same time, in order to improve the distortion of the internal electric field intensity of the EMU cable terminal, nonlinear materials and high dielectric materials are used to replace the stress tube respectively, and the optimization effects of the two materials on the internal distortion electric field of the cable terminal are studied. The results show that the defects are closer to the multi-layer combination area among main insulation layer, stress tube layer and outer semiconducting layer of the cable terminal, the electric field distortion of multi-layer combination area become greater. With the increasing of defect size, the electric field intensity also gradually increases. However, the inner defect location and size have less effect on the electric field intensity along the cable terminal umbrella skirt. It is found that both nonlinear materials and high dielectric materials can effectively optimize the electric field intensity of cable terminal and improve the electric field distortion. This work can be helpful for operation and design of high-speed EMU’s cable terminal.

Terahertz Bessel beam generator.

The Bessel beam has broad application prospects in wireless energy transmission and high-speed communications. The traditional Bessel beam generation method has the problems of large volume, low efficiency, and complex manufacturing. To solve the above problems, we present a terahertz Bessel beam generator based on the reflective metasurface, which is composed of a metal pattern, dielectric layer, and bottom metal plate. Under the incidence of right circularly polarized (RCP) wave, the zero-order Bessel beam and zero-order symmetric double Bessel beam are generated. It can be found that the bottom angle of the axicon of the first-order Bessel beam is inversely proportional to the propagation distance of the Bessel beam. Comparing the electric field intensity distribution, phase distribution, and mode purity of the second-order Bessel beam and the second-order vortex beam in different observation planes, it can be seen that the energy of the higher-order Bessel beam is more concentrated and the field distribution is more stable than those of the ordinary vortex beam. The reflective terahertz Bessel beam generator has potential application value in terahertz wireless communications, measurement, radar detection, and imaging.

Simulation Study on Safe Distance between Crane Boom and High-Voltage Line Based on Electric Field Intensity

Aiming at the safety accident caused by the close distance between the crane arm and the high-voltage line when the crane is working near the high-voltage transmission line, this paper proposes a simulation model of the electric field intensity distribution of the high-voltage transmission line. First, through the simplification and equivalent treatment of the high-voltage line, the simulation modeling, and analysis of the electric field around the high-voltage line are carried out. Then, the theory of solving the electric field intensity of any point around the high-voltage line based on the charge simulation method is deduced, and the conclusion that the electric field intensity at the equal distance of the high-voltage line is approximately equal is obtained. Furthermore, the influence of the crane on the electric field strength of a high-voltage line is analyzed, and the linear correction function of electric field strength is obtained. Based on the research in this paper, the field strength sensor can be used to obtain the value of the electric field strength, calculate the distance between the crane and the high-voltage line, and make a safety warning response. The simulation results verify the feasibility and effectiveness of the proposed model and method.

Generation and measurement of irregular polygonal perfect vortex optical beam based on all-dielectric geometric metasurface.

The perfect optical vortex (POV) beam carrying orbital angular momentum with topological charge-independent radial intensity distribution possesses ubiquitous applications in optical communication, particle manipulation, and quantum optics. But the mode distribution of conventional POV beam is relatively single, limiting the modulation of the particles. Here, we originally introduce the high-order cross-phase (HOCP) and ellipticity γ into the POV beam and construct all-dielectric geometric metasurfaces to generate irregular polygonal perfect optical vortex (IPPOV) beams following the trend of miniaturization and integration of optical systems. By controlling the order of the HOCP, conversion rate u, and ellipticity factor γ, various shapes of IPPOV beams with different electric field intensity distributions can be realized. In addition, we analyze the propagation characteristics of IPPOV beams in free-space, and the number and rotation direction of bright spots at the focal plane give the magnitude and sign of the topological charge carried by the beam. The method does not require cumbersome devices or complex calculation process, and provides a simple and effective method for simultaneous polygon shaping and topological charge measurement. This work further improves the beam manipulation ability while maintaining the characteristics of the POV beam, enriches the mode distribution of the POV beam, and provides more possibilities for particle manipulation.

Multidimensional structural coloration from hierarchically designed plasmonic structures

We propose a photonic strategy for multidimensional structural coloration that responds to varying illumination conditions. Both theoretical and experimental results verified that the combination of a metal/dielectric/metal cavity with a one-dimensional (1D) metal grating can increase the degree of freedom of structural coloration. We fabricated Ag/MgF2/Ag cavities coupled to 1D Ag gratings (pitches of 400, 570, and 800 nm) and obtained their photonic band dispersions (i.e., angle-resolved reflectance spectra) to unravel their mode characteristics. The 1D Ag grating and Ag/MgF2/Ag cavity induced surface plasmon polariton (SPP) and Fabry–Perot cavity modes, respectively. Notably, only a cavity mode emerged in the s-polarization and gradually blueshifted with increasing angle, whereas in the p-polarization, both SPP and cavity modes appeared and shifted oppositely with changes in the angle, leading to intricate color patterns at different wavelengths, angles, and polarizations. To further understand the effect of each mode upon structural coloration, we obtained the distribution of electric field intensity using rigorous coupled-wave analysis simulation, which identified multiple photonic bands in the p-polarization as various SPP-mediated hybrid modes.