Electric Field Enhancement Research Articles

Extraordinary terahertz transmission and field enhancement via hybrid surface plasmon coupling in rhombic and bow-tie composite aperture metasurface

Metasurface that achieves extraordinary terahertz transmission (ETT) and local electric field enhancement (FE) holds significant potential for terahertz studies involving extremely low concentrations of target materials. In this study, we explore a composite aperture metasurface capable of both ETT and local FE. By inserting bow-tie apertures in the “minimum-resonance” zone between four adjacent rhombic lattices, a local FE factor is achieved. Notably, adjusting the configuration of the bow-tie aperture enhances the coupling between surface plasmons, thereby expanding the transmission bandwidth. Through parameter optimization, the metasurface achieves a peak transmission exceeding 95% and a transmittance above 80% in the frequency range of 2.44–3.65 THz, while simultaneously exhibiting a maximum local FE factor of 1005 at 3.45 THz. This approach offers a promising avenue for the design of metasurfaces for spectroscopy and biosensor applications.

Point-cloud clustering and tracking algorithm for radar interferometry

In data mining, density-based clustering, which entails classifying datapoints according to their distributions in some space, is an essential method to extract information from large datasets. With the advent of software-based radio, ionospheric radars are capable of producing unprecedentedly large datasets of plasma turbulence backscatter observations, and new automatic techniques are needed to sift through them. We present an algorithm to automatically identify and track clusters of radar echoes through time, using , a celebrated density-based clustering method for noisy point clouds. We demonstrate our algorithm's efficiency by tracking turbulent structures in the E-region ionosphere, the so-called radar aurora. Through conjugate auroral imagery, as well as satellite observations, we demonstrate that the observed turbulent structures generally track the motion of auroras. What is more, the radar aurora bulk motions exhibit key qualities of auroral electric field enhancements that have previously been observed with various instruments. We present preliminary statistical results using our method, and briefly discuss the method's limitations and potential future adaptations. Published by the American Physical Society 2024

Single-step and parallel high-speed fabrication for Au micro-/nanostructures.

Patterns fabricated with Au nanoparticles (Au NPs) exhibit significant potential in fields such as micro-optics and bioelectronics. However, the current manufacturing methods still suffer from complex processes and low efficiency. In this work, we propose a high-speed manufacturing method for Au micro-/nanostructures based on spatiotemporal focusing and maskless lithography, achieving a throughput of 0.5 mm2/min. The surface electric field enhancement of the structure was confirmed using Raman spectroscopy, indicating that this method holds significant promise for metasurface, biosensing, and plasmonic chemistry.

Boosting Light-Matter Interactions in Plasmonic Nanogaps.

Plasmonic nanogaps in strongly coupled metal nanostructures can confine light to nanoscale regions, leading to huge electric field enhancement. This unique capability makes plasmonic nanogaps powerful platforms for boosting light-matter interactions, thereby enabling the rapid development of novel phenomena and applications. This review traces the progress of nanogap systems characterized by well-defined morphologies, controllable optical responses, and a focus on achieving extreme performance. The properties of plasmonic gap modes in far-field resonance and near-field enhancement are explored and a detailed comparative analysis of nanogap fabrication techniques down to sub-nanometer scales is provided, including bottom-up, top-down, and their combined approaches. Additionally, recent advancements and applications across various frontier research areas are highlighted, including surface-enhanced spectroscopy, plasmon-exciton strong coupling, nonlinear optics, optoelectronic devices, and other applications beyond photonics. Finally, the challenges and promising emerging directions in the field are discussed, such as light-driven atomic effects, molecular optomechanics, and alternative new materials.

Deep Learning-Based Electric Field Enhancement Imaging Method for Brain Stroke

In clinical settings, computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET) are commonly employed in brain imaging to assist clinicians in determining the type of stroke in patients. However, these modalities are associated with potential hazards or limitations. In contrast, microwave imaging emerges as a promising technique, offering advantages such as non-ionizing radiation, low cost, lightweight, and portability. The primary challenges faced by microwave tomography include the severe ill-posedness of the electromagnetic inverse scattering problem and the time-consuming nature and unsatisfactory resolution of iterative quantitative algorithms. This paper proposes a learning electric field enhancement imaging method (LEFEIM) to achieve quantitative brain imaging based on a microwave tomography system. LEFEIM comprises two cascaded networks. The first, based on a convolutional neural network, utilizes the electric field from the receiving antenna to predict the electric field distribution within the imaging domain. The second network employs the electric field distribution as input to learn the dielectric constant distribution, thereby realizing quantitative brain imaging. Compared to the Born Iterative Method (BIM), LEFEIM significantly improves imaging time, while enhancing imaging quality and goodness-of-fit to a certain extent. Simultaneously, LEFEIM exhibits anti-noise capabilities.

Shadow Mask Molecular Beam Epitaxy for In‐Plane Gradient Permittivity Materials

AbstractInfrared spectroscopy currently requires the use of bulky, expensive, and/or fragile spectrometers. For gas sensing, environmental monitoring, or other applications, an inexpensive, compact, robust on‐chip spectrometer is needed. One way to achieve this is through gradient permittivity materials, in which the material permittivity changes as a function of position in the plane. Here, synthesis of infrared gradient permittivity materials is demonstrated using shadow mask molecular beam epitaxy. The permittivity of the material changes as a function of position in the lateral direction, confining varying wavelengths of infrared light at varying horizontal locations. An electric field enhancement corresponding to wavenumbers ranging from ≈650 to 900 cm−1 over an in‐plane width of ≈13 µm on the flat mesa of the sample is shown. An electric field enhancement corresponding to wavenumbers ranging from ≈900 to 1250 cm−1 over an in‐plane width of ≈13 µm on the slope of the sample is also shown. These two different regions of electric field enhancement develop on two opposite sides of the material. This demonstration of a scalable method of creating in‐plane gradient permittivity material can be leveraged for the creation of a variety of miniature infrared devices, such as an ultracompact spectrometer.

Quantifying the ultimate limit of plasmonic near-field enhancement

Quantitatively probing the ultimate limit of near-field enhancement around plasmonic nanostructures remains elusive, despite more than five decades since the discovery of surface-enhanced Raman scattering. Theoretical calculations have predicted an ultimate near-field enhancement exceeding 1000 using the best plasmonic material silver, but experimental estimations disperse by orders of magnitude. Here, we design a high-quality silver plasmonic nanocavity with atomic precision and precisely quantify the upper limit of near-field enhancement in ~1 nm junctions. A hot-spot averaged Raman enhancement of 4.27 × 1010 is recorded with a small fluctuation, corresponding to an averaged electric field enhancement larger than 1000 times. This result quantitatively delineates the ultimate limit of plasmonic field enhancement around plasmonic nanostructures, establishing a foundation for diverse plasmon-enhanced processes and strong light-matter interactions at the atomic scale.

Fast On-Site Speciation and High Spatial Resolution Imaging of Labile Arsenic in Freshwater and Sediment Using the DGT-SERS Sensor.

Diffusive gradients in thin films (DGT) technique is renowned for in situ passive sampling but not for rapid on-site analysis, whereas surface-enhanced Raman spectroscopy (SERS) excels in ultrasensitive on-site detection but is limited by substrate contamination from complex matrices. Here, a hierarchical nanostructure of silver (Ag) mirror-supported large Ag nanoparticles (∼120 nm) was grown in situ in polyacrylamide hydrogel with a restricted pore size (PAM/Ag mirror/AgNPs) to serve as both the DGT binding phase and the SERS substrate. The substrate exhibited a maximum electric field enhancement factor of 9.9 × 108 and a signal relative standard error of 4.8%. Using the DGT-SERS sensor, As(III) and As(V) in freshwater were simultaneously detected at limits of 0.9 and 0.8 μg L-1, respectively, applicable across a wide range of environmental conditions. The DGT-SERS effectively mitigated the interfacial reduction of As(V) caused by humic acid by excluding it from plasmonic hotspots through size exclusion of the diffusive layer. The Raman analysis of a DGT sample in the field requires only 2 s using a portable spectrometer without DGT device disassembly. More importantly, the DGT-SERS captured the first two-dimensional image of As(III) and As(V) in one DGT at the micron scale resolution, revealing their spatially supplementary distribution patterns at the sediment-water interface. This study paves the way for next-generation speciation imaging DGT and the application of SERS in complex environments.

Enhancing the Photocatalytic Performance for Norfloxacin Degradation by Fabricating S-Scheme ZnO/BiOCl Heterojunction

Construction of S-scheme heterojunctions can effectively limit the recombination of photogenerated e− and h+, thus improving photocatalytic activity. Therefore, S-scheme ZnO/BiOCl (molar ratio = 1:2) n–n heterojunctions were synthesized via a hydrothermal–hydrolysis combined method in this study. The physical and chemical properties of the ZnO/BiOCl heterojunctions were characterized by XRD, XPS, SEM, TEM, DRS, N2 adsorption–desorption and ESR. Additionally, the photoelectric performances of ZnO/BiOCl heterojunctions were investigated with TPR, M–S plot and EIS. The results show that photocatalytic degradation of NOR by ZnO/BiOCl reached to 94.4% under simulated sunlight, which was 3.7 and 1.6 times greater than that of ZnO and BiOCl, respectively. The enhanced photodegradation ability was attributed to the enhancement of the internal electric field between ZnO and BiOCl, facilitating the active separation of photogenerated electrons and holes. The radical capture experiments and ESR results illustrate that the contribution of reactive species was in descending order of ·OH > h+ > ·O2− and a possible mechanism for the photodegradation of NOR over S-scheme ZnO/BiOCl heterojunctions was proposed.

High-performance SERS substrate based on gold nanoparticles-decorated micro/nano-hybrid hierarchical structure

Owing to its excellent localized surface plasmon resonance (LSPR) effect, noble metal nanoparticles (NPs) find extensive application in the preparation of surface-enhanced Raman scattering (SERS) substrates. However, due to process limitations, the practicality and testing effectiveness of SERS substrates still leaves much to be desired. Here, a wafer-scale gold (Au) NPs silicon (Si) micro/nano-hybrid structured substrate is prepared. This is achieved through two-step etching, followed by decorating Au-NPs onto the structure via self-assembly process induced by de-wetting. Finite-difference time-domain (FDTD) simulations reveal that the significant enhancement of local electric field in the voids between Au-NPs and Si is crucial for enhancing SERS. Using Rhodamine 6G (R6G) as the probe molecule, performance of the fabricated SERS substrate is investigated. It demonstrates a minimum detection limit of 10−11 M, with a calculated enhancement factor of 4.40 × 108, indicating its high sensitivity. The minimum relative standard deviation for the substrate is 5.254 %. After 20 days of placement, the SERS performance show tiny variation. Even after four cycles of cleaning experiments, it still maintains outstanding SERS performance. This demonstrates its excellent stability, uniformity and reusability. Our research provides guidance for the efficient and low-cost fabrication of high-performance SERS substrates.

Quantum mechanical effects in plasmonic sub-nanometer cavities formed by a tip and substrate structure

Enhancing local field intensity through light field compression is one of the core issues in surface plasmon-enhanced spectroscopy. The theoretical framework for the nanostructure composed of a tip and a substrate has predominantly relied on classical electromagnetic models, ignoring the electron tunneling effect. In this paper, we investigate the plasmonic near-field characteristics in the sub-nanometer cavity formed by the tip and the substrate using a quantum-corrected model. Additionally, we analyze the local electric field and Raman enhancement when hexagonal boron nitride (h-BN) monolayer is used as a decoupling layer for the nanocavity. The results indicate that classical electromagnetic theory fails to accurately describe the plasmonic electric field in smaller sub-nanometer gaps. When the gap is reduced to 0.32 nm, the quantum-corrected model shows that the local electric field in the sub-nanometer cavity is significantly reduced due to the tunneling current, aligning more closely with experimental results. Moreover, adding a high-barrier h-BN layer effectively prevents the occurrence of tunneling current, allowing for a strong local electric field even when the gap is less than 0.32 nm. The calculated maximum Raman enhancement reaches up to 15 orders of magnitude. Our research results provide a deep understanding of quantum mechanical effects in tip-enhanced spectroscopy systems, enabling the potential applications based on quantum plasmons in nanocavity.

High-performance electric energy storage in BiFeO3–Ba(Ti0.8Zr0.2)O3 relaxor ferroelectric ceramics

Perovskite relaxor ferroelectrics have been widely developed for energy storage applications due to their exceptional dielectric properties. This work explores the energy storage performance, thermal stability, and structural evolution in (1-x)BiFeO3–x Ba(Ti0.8Zr0.2)O3 ceramics (x = 0.3, 0.4, 0.5, and 0.6) via modulating Ba(Ti0.8Zr0.2)O3 (BZT) concentration. An enhancement of breakdown electric field from 120 kV/cm at x = 0.3–220 kV/cm at x = 0.5 can be attributed to increased grain boundaries and nanodomains as electric barriers to inhibit charge mobility. A high recoverable energy density of 5.9 J/cm3 and a high energy efficiency of 86.2 % were achieved at x = 0.5 and 0.6, respectively. The structure shifts from ferroelectric rhombohedral R3c symmetry toward a coexistence of nonpolar symmetries (including tetragonal P4/mmm, cubic Pm-3m, and orthorhombic Pbnm) with increasing BZT. The integration of BZT in BiFeO3 demonstrates to break the long-range order and promote the formation of polar nanoregions and nanodomains, leading to a high-efficiency energy storage.

Incorporation of Gold Nanoparticle into ZnO Electron Transport Layer to Improve Performance of Hybrid Bulk Heterojunction Solar Cell

Abstract We have investigated the effect of localized surface plasmon resonance (LSPR) from gold nanoparticles incorporated into the electron transport layer (ETL) of zinc oxide (ZnO) on charge carrier transport in order to improve the performance of inverted hybrid bulk-heterojunction solar cells. Synthesis of gold nanoparticles capped by 3-mercaptopropionic acid (AuMPA) and oleylamine (AuOA) was carried out by use of the reduction method and the fabrication of solar cell device with the configuration of ITO/ZnO:AuNPs/P3HT:PCBM/PEDOT:PSS/Ag was done by spin coating and thermal evaporation techniques. The absorbance spectra show a plasmonic peak of AuMPA in solution at 521 nm, while AuOA has a plasmonic peak at 531 nm, with both solutions showing a red-wine color. In our investigation, the incorporation of AuMPA about 2.65wt% or AuOA about 3.5 wt% in the ZnAc solution is quite stable. With the addition of 1.77 wt% AuMPA, the fabricated devices show a significant improvement at short circuit condition (JSC) from 46.67 mA/cm2 to 83.11 mA/cm2, resulting in an increase in power conversion efficiency (PCE) from 5.64% to 9.00% under the illumination of 100 mW/cm2 simulated solar irradiation. While the AuOA addition of 2.65 wt%, the JSC increased from 22.67 mA/cm2 to 44.12 mA/cm2 along with an improvement of PCE from 2.71% to 5.32%. The experiment results suggest that the electron mobility or charge carrier transport to the indium tin oxide (ITO) cathode is improved by the local electric field enhancement around the zinc oxide (ZnO) electron transport layer due to the effect of gold nanoparticles (AuNPs).

The Generation of Seismogenic Anomalous Electric Fields in the Lower Atmosphere, and Its Application to Very-High-Frequency and Very-Low-Frequency/Low-Frequency Emissions: A Review

The purpose of this paper is, first of all, to review the previous works on the seismic (or earthquake (EQ)-related) direct current (DC) (or quasi-stationary) electric fields in the lower atmosphere, which is likely to be generated by the conductivity current flowing in the closed atmosphere–ionosphere electric circuit during the preparation phase of an EQ. The current source is electromotive force (EMF) caused by upward convective transport and the gravitational sedimentation of radon and charged aerosols injected into the atmosphere by soil gasses during the course of the intensification of seismic processes. The theoretical calculations predict that pre-EQ DC electric field enhancement in the atmosphere can reach the breakdown value at the altitudes 2–6 km, suggesting the generation of a peculiar seismic-related thundercloud. Then, we propose to apply this theoretical inference to the observational results of seismogenic VHF (very high frequency) and VLF/LF (very low frequency/low frequency) natural radio emissions. The formation of such a peculiar layer initiates numerous chaotic electrical discharges within this region, leading to the generation of VHF electromagnetic radiation. Earlier works on VHF seismogenic radiation performed in Greece have been compared with the theoretical estimates, and showed a good agreement in the frequency range and intensity. The same idea can also be applied, for the first time, to seismogenic VLF/LF lightning discharges, which is completely the same mechanism with conventional cloud-to-ground lightning discharges. In fact, such seismogenic VLF/LF lightning discharges have been observed to appear before an EQ. So, we conclude in this review that both seismogenic VHF radiation and VLF/LF lightning discharges are regarded as indirect evidence of the generation of anomalous electric fields in the lowest atmosphere due to the emanation of radioactive radon and charged aerosols during the preparation phase of EQs. Finally, we have addressed the most fundamental issue of whether VHF and VLF/LF radiation reported in earlier works is either of atmospheric origin (as proposed in this paper) or of lithospheric origin as the result of microfracturing in the EQ fault region, which has long been hypothesized. This paper will raise a question regarding this hypothesis of lithospheric origin by proposing an alternative atmospheric origin outlined in this review. Also, the data on seismogenic electromagnetic radiation and its inference on perturbations in the lower atmosphere will be suggested to be extensively integrated in future lithosphere–atmosphere–ionosphere coupling (LAIC) studies.

Low-cost Ag/ZnO nanosheets arrays as sensitive and recyclable surface-enhanced Raman scattering substrates

The development of surface-enhanced Raman scattering (SERS) substrate based on metal/semiconductor nanostructured platforms has emerged as a promising technique for achieving highly sensitive and recyclable detection across various fields, including environmental monitoring, food safety, biomedical diagnostics, and the preservation of cultural heritage. However, the design and fabrication of cost-effective metal/semiconductor nanostructures suitable for SERS substrates remain a formidable challenge. In this study, a low-cost, recyclable SERS substrate based on Ag nanoparticle decorated ZnO nanosheets (Ag/ZnO NSs) arrays was developed using hydrothermal growth and photochemical reduction approaches. The optimized Ag/ZnO NSs arrays demonstrated local electric field enhancement and multi-path charge transfer, ensuring an enhancement factor of 107 and a detection limit of 10−10 mol/L for crystal violet molecules. This research not only sheds light on the economical production of metal/semiconductor SERS substrates but also paves the way for a broader spectrum of SERS-based detection applications in diverse fields.

Cellulose-based mugwort biochar constructs p-n heterojunction micro interfaces to regulate the photocatalytic oxidation of As(III) by ferromanganese ions

The utilization of a low-cost common waste biomass, mugwort, with a porous structure is important for the treatment of Arsenic (III) pollution in the aquatic environment. In this study, mugwort straw was first delignified to expose more hydroxyl groups, then loaded with MnOOH and α − FeOOH and constructed with p − n heterojunctions on cellulosic biochar microinterfaces. The successful formation of p − n heterojunction effectively enhances the electric field enhancement inside the photocatalyst, promotes charge transfer and suppresses the recombination of photogenerated carriers. Application of high-energy electron beam irradiation of FMBC−LR2 to modulate the generation and dominant mechanism of Fe and Mn in the reaction system. The results showed that Mn3+ underwent disproportionation reaction to form Mn2+ and Mn4+. Among them, Mn2+ led to the formation of MnFe2O4, while Mn4+ exhibited stronger oxidizing properties that could promote the transformation of Fe2+ to Fe3+, thus allowing more Fe3+ to participate in the photocatalytic oxidation of As(III) in a synergistic manner. As(III) oxidation efficiency increased 9.18 times after delignification treatment (FMBC−LR2) and 12.31 times after high-energy electron beam irradiation (FMBC−LR2 − 650) as compared to mugwort straw biochar (BC). In addition, the EPR assay results indicated that ·O2−, ·OH, and 1O2 acted together in the As(III) reaction. This provides new insights into the remediation of composite modified biochar in water bodies and a new environmentally friendly strategy for the comprehensive utilization of straw materials.

Insights into the Effect of a Microwave Field on the Properties of Modified γ-Alumina: A DFT Study

γ-Alumina is often used as a support for hydrodesulfurization catalysts due to its excellent performance. During the catalytic reaction, the strong surface acidity of γ-alumina can induce a strong interaction between the active phase and the support. The reaction activity of the catalyst can be affected by changing the present mode of the active phase on the surface of the support. The (110) crystal plane, acting as the strongest acidity plane of γ-alumina, was selected for modification. The supports modified with boron and phosphorus were successfully constructed, and the acid strengths were quantified by simulating the adsorption of the relevant probe molecules: pyridine in correlation with surface electronic properties via density functional theory. The surface adsorption energy calculation shows that the boron-modified surface is able to moderately reduce the adsorption capacity of alumina, while that of the surface modified by phosphorus is found to be enhanced over the sites of a tetrahedral coordination structure; however, at the other unsaturated Al sites, this is obviously reduced. The results of introducing electric fields imply that applying horizontal electric fields changes the surface acidity of alumina under the premise of a stable structure. With the enhancement of the horizontal electric fields, the adsorption capacity of tetra-coordination sites on the original surface gradually decreases, while those of the others gradually increases. However, for the boron-modified surface, introducing horizontal electric fields can reduce the adsorption capacity of all sites. Hence, microwave-electric-field-assisted modification of B further reduces the surface acidity of alumina, making it beneficial for deep hydrodesulfurization reactions.

Organic Heterophase Composites Induced Sulfur Vacancies and Internal Electric Field Enhancement for Advanced Magnesium Storage of Copper Sulfide Cathodes

AbstractRechargeable magnesium‐ion batteries (MIBs) hold significant promise for safe and efficient large‐scale energy storage, but the lack of high‐performance cathodes hinders their development for practical applications. In this work, a series of nanocomposites consisting of π‐conjugated perylene‐3,4,9,10‐tetracarboxylic dianhydride annealed at 450 °C and copper sulfide (CuSP) are synthesized solvothermally to explore their utility as a host for Mg2+ storage in MIBs. The carbonyl organics in the hybrid materials modify the predominant CuS phase, expanding interlayer spacing and enriching sulfur vacancies through modifications of the internal electric field. This synergistic interaction enhances magnesium storage performance and accelerates reaction kinetics. Using chlorine‐free Mg[B(hfip)4]2/DME electrolytes, the CuSP91 cathode containing an appropriate organic content displays a remarkably high reversible capacity of 285 mAh g−1 at 50 mA g−1, and demonstrates a stable capacity of 220 mAh g−1 at 100 mA g−1, surpassing pure CuS cathode in terms of shorter activation time. The CuSP91 cathode maintains a discharge capacity of 55 mAh g−1 over 1000 cycles at 500 mA g−1. A co‐redox mechanism is revealed through in/ex situ investigations and analyses. Overall, this research contributes valuable insights targeting the development of advanced organic–inorganic hybrid composite cathode materials in next‐generation energy storage systems.

Nitrogen Fixation by Atmospheric Microwave Plasma with Local Electric Field Enhancement

Abstract Nitrogen fixation by atmospheric microwave plasma is a promising green technology. However, the energy consumption of nitrogen fixation driven by microwave plasma is still too high in existing reports, and there is a lack of effective methods to reduce it. In this paper, a method of local electric field enhancement in atmospheric microwave plasma is reported, which is achieved in an optimized metal array structure that can increase the electric field intensity by 385 times. The experimental results show that the reduction of energy consumption reaches up to 20% and the nitrogen oxide production increases by up to 26% with the local electric field enhancement. The achieved energy consumption is as low as 1.78 MJ/mol with a corresponding nitrogen oxide production of 3.53%. To the best of our knowledge, this is the first study to explore the role of local electric field enhancement on nitrogen fixation, and the energy consumption in this study is the lowest among the existing studies of nitrogen fixation by atmospheric pressure microwave air plasma.

Comparative Analysis of Two Different MIM Configurations of a Plasmonic Nanoantenna

AbstractTwo plasmonic nanoantenna configurations—nanodisk and nanostrip arrays—in a metal–insulator-metal (MIM) setup were proposed, optimized, and compared by simulating their optical properties in three-dimensional models using COMSOL Multiphysics software. The optical responses, including electric field enhancement, absorption, reflection, and transmission spectra, were systematically investigated. Optimized geometrical parameters led to a significant enhancement of the electric field within the gap layers and almost perfect light absorptance for both structures. The results showed that the enhancement of the electric field depends on the polarization of the incident light. For both polarizations, the periodic circular nanodisk array showed a stronger field enhancement with an electric field enhancement factor of 6.6 × 106 and TE polarization, and a larger absorptance of 98% at its dipole resonance wavelength, indicating the fundamental plasmonic mode. In addition, weaker resonant modes were observed in the absorptance and reflectance spectra of both nanostructures, with the nanostrips exhibiting sharper and stronger higher-order modes, making them suitable for applications requiring precise wavelength selectivity and narrow-band responses. Despite their different geometric shapes, both structures exhibited similar optimized metal film thickness and nanoparticle height, comparable modes in number and position, and identical optimized light incidence angles. Furthermore, increasing the dielectric gap layer thickness and optimizing it to a specific value revealed its ability to measure the refractive index, making it a promising candidate for sensing applications.