Plasmonics最新文献

{"title":"Dual-Ring Resonator-Assisted MIM Plasmonic Platform for High-Sensitivity Temperature Sensing","authors":"Pejman Piraan,&nbsp;Mohammad Soroosh,&nbsp;Shahrzad Ajabi,&nbsp;Haraprasad Mondal","doi":"10.1007/s11468-026-03456-3","DOIUrl":"10.1007/s11468-026-03456-3","url":null,"abstract":"<div><p>This paper proposes a high-sensitivity and compact plasmonic refractive index sensor based on a metal–insulator-metal (MIM) waveguide and two MIM ring resonators. The optimal radii of the resonators are determined via a parameter sweep to achieve near-zero transmission and strong resonance at 1550 nm. The sensor exhibits a refractive index sensitivity of 1540 nm/RIU, a figure of merit of 91 RIU⁻¹, and a quality-factor of 121 for refractive indices near <i>n</i> = 1.33. Using ethanol as a thermos-optic material, the presented sensor can detect small temperature changes with a temperature sensitivity of 0.61 nm/°C. Compared to previous MIM-based sensors, the proposed structure achieves competitive refractive index sensitivity and superior temperature sensitivity while maintaining structural simplicity. Due to its compact footprint of 2.5 μm² and remarkable sensing capabilities, the proposed sensor has high potential for use in a wide range of industrial, medical, and environmental applications.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 9","pages":"3567 - 3578"},"PeriodicalIF":5.6,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149078870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Situ Generated Nanogold Sol SERS Analysis of Trace APO with AgNC@COF Nanocatalytic Probe","authors":"Zhenmin Li,&nbsp;Ruitao Zhu,&nbsp;Chongning Li,&nbsp;Aihui Liang,&nbsp;Zhiliang Jiang","doi":"10.1007/s11468-026-03437-6","DOIUrl":"10.1007/s11468-026-03437-6","url":null,"abstract":"<div><p>Silver nanoclusters (AgNC) and polytetrafluoroethylene (PTFE) were employed as the nanomatrix of positive and negative electrodes respectively, ammonium pentadecafluorooctanoate (APO) as the template molecule, and trialdehyde resorcinol (Tp) and biphenylamine (BD) as functional monomers to synthesize two new surface molecularly imprinted covalent organic framework nanoprobes (MCOF_P and MCOF_N). The slope procedure was used to evaluate the catalysis of those nanoprobes for the gold nanoparticle (AuNP) reaction of sodium formate (SF)-HAuCl₄ with surface-enhanced Raman scattering (SERS) monitoring. The piezoelectric nanocatalysis of MCOF_P was observed firstly. The mixture of two probes exhibited molecular recognition, nanocatalytic, piezoelectric nanocatalysis and triboelectric nanogenerator tetra-functions. Upon addition of APO, the catalytic performance of the mixture system was further enhanced, mainly due to TENG amplification. Based on these findings, a new TENG-based SERS quantitative analytical method was developed for trace detection of 0.05–0.50 nmol/L APO.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 10","pages":"3893 - 3905"},"PeriodicalIF":5.6,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Numerical Analysis of a Chemically Stable and Highly Sensitive Ag/Pd Bimetallic SPR Sensor with ZnO Overlayer for Pathogenic Escherichia Coli Detection","authors":"Debjyoti Banik,&nbsp;Md. Jahirul Islam,&nbsp;Suvodip Kundu Arnob","doi":"10.1007/s11468-026-03453-6","DOIUrl":"10.1007/s11468-026-03453-6","url":null,"abstract":"<div><p>Pathogenic Escherichia coli (E. coli) contamination in food and water supplies poses a severe threat to global public health, necessitating the development of rapid and ultra-sensitive detection methods. The present work proposes a high-performance surface plasmon resonance (SPR) biosensor based on BK7/Ag/Pd/ZnO heterostructure specially designed to detect E. coli in high-refractive-index conditions (n_s = 1.388). The sensor design employs a bimetallic Ag/Pd stack to incorporate the best plasmonic characteristics of silver and the chemical stability of palladium, with a zinc oxide (ZnO) dielectric overlayer to improve the confinement of the evanescent fields. Based on numerical analysis through finite-difference time-domain (FDTD) simulations, the optimal structure, which consists of 45 nm Ag, 15 nm Pd, and 1 nm ZnO layers, achieves an angular sensitivity of 256.34 deg/RIU, Quality Factor (QF) of 163.45 RIU⁻¹, and Detection Accuracy (DA) of 8.66. The simpler structure not only surpasses more complicated multi-layer structures but is also easier to fabricate since it still follows the layer-by-layer approach despite being a simpler configuration for detecting Escherichia coli, making it more practical in terms of scalable production. Moreover, the device showed excellent reliability, achieving a linear regression coefficient (R²) value of 0.9943 throughout the whole refractive index spectrum. The high sensitivity, practicality, and reliability of the proposed sensor confirm its applicability real-time monitoring to ensure food safety and safeguard public health.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 10","pages":"3877 - 3892"},"PeriodicalIF":5.6,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176336","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermally Engineered Ag Nanostructures on Flexible PVA Films for SERS Applications","authors":"Sarumathi Muthuvel,&nbsp;Balaji R,&nbsp;Shenbagamoorthi S,&nbsp;Dhanpal Jayram Naidu,&nbsp;Shashi Kant Dargar","doi":"10.1007/s11468-026-03452-7","DOIUrl":"10.1007/s11468-026-03452-7","url":null,"abstract":"<div><p>A flexible polyvinyl alcohol (PVA)-based surface-enhanced Raman spectroscopy (SERS) substrate was fabricated by solution casting, followed by Ag deposition using DC magnetron sputtering and controlled thermal annealing. X-ray diffraction analysis confirmed the formation of face-centered cubic <b>(</b>fcc) Ag with a dominant (111) orientation after thermal treatment, indicating improved crystallinity. The hydroxyl groups present in the PVA matrix, as identified by FTIR analysis, may promote the adsorption of analyte molecules through hydrogen-bonding interactions. Morphological analysis revealed substantial restructuring of the Ag layer after annealing, resulting in a finer, and more densely distributed Ag nanoisland morphology. Elemental analysis confirmed the presence and distribution of Ag on the polymer substrate. The SERS performance was evaluated using crystal violet (CV) as a model analyte over a concentration range of 10^− 2–10^− 6M. The fabricated substrate achieved a limit of detection (LOD) of 6.4 × 10^− 6 M and exhibited a linear response with R² = 0.91785. An enhancement factor of 3.659 × 10⁷ was achieved, demonstrating substantial Raman signal enhancement. The substrate also exhibited good spatial reproducibility, with a relative standard deviation (RSD) of 9.9% across multiple measurement positions, and retained measurable SERS activity after 20 days of storage. The enhanced Raman performance is associated with annealing-induced restructuring of the Ag layer and the resulting changes in nanostructure morphology. The results demonstrate the potential of the flexible Ag/PVA substrate as a simple, scalable, and cost-effective platform for plasmonic sensing applications.</p><h3>Graphical Abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 10","pages":"3863 - 3875"},"PeriodicalIF":5.6,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hybrid Deep Learning-Assisted Dual-Core D-Shaped PCF-SPR Sensor for High-Performance Refractive Index and Temperature Sensing","authors":"Kaipeng Wang,&nbsp;Yingchao Liu,&nbsp;Peigang Cao","doi":"10.1007/s11468-026-03449-2","DOIUrl":"10.1007/s11468-026-03449-2","url":null,"abstract":"<div><p>This paper designs a surface plasmon resonance dual-parameter sensor based on a dual-core D-type photonic crystal fiber, and proposes a hybrid deep learning prediction model. The sensor constructs two independent sensing channels for refractive index and temperature detection. The upper channel uses an Au-TiO<span>(_2)</span> composite coating for refractive index detection, and the lower channel uses an Au-Polydimethylsiloxane (PDMS) composite structure for temperature detection. From the structural perspective, the sensor achieves complete physical decoupling of the two parameters and the crosstalk between the channels is less than 1 nm. The sensor has a maximum sensitivity of 19000 nm/RIU within the refractive index range of 1.30 1.41 RIU, and a maximum sensitivity of 27.1 nm/<span>(^circ )</span>C within the temperature range of -19 - 100 <span>(^circ )</span>C. Moreover, the structural parameters such as the radius of the air holes, the hole spacing, and the polishing depth all have excellent tolerance. In response to the low computational efficiency problem of the traditional finite element method, this paper further proposes a hybrid deep learning model named HybridOpticalNet, which integrates a residual multi-layer perceptron and a one-dimensional convolutional neural network. The model adopts a dual-branch parallel architecture to extract global structural features and local spectral features, achieving deep complementary fusion of the two types of information. The prediction coefficient <span>(R^2)</span> of the model for the dual-channel loss spectrum is above 0.998, the average absolute error is less than 30 dB/m, and the spectral prediction can be completed within milliseconds, with a significant improvement in efficiency compared to traditional numerical methods. This sensor has high sensitivity, low crosstalk, and good process tolerance. Combined with the deep learning model, it can complete the rapid design and performance optimization of multi-parameter PCF-SPR sensors, and has broad application prospects in biochemical detection and environmental monitoring fields.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 8","pages":"3349 - 3370"},"PeriodicalIF":5.6,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanism-resolved LSPR Benchmarks for Separating Bulk-index Response, Protein-layer Loading, and Silver-tarnish Artifacts","authors":"Anshuman Khiriya","doi":"10.1007/s11468-026-03448-3","DOIUrl":"10.1007/s11468-026-03448-3","url":null,"abstract":"<div><p>Localized surface plasmon resonance (LSPR) sensing commonly interprets a resonance red shift as interfacial binding, although bulk-medium drift, nonspecific dielectric loading and metal-surface transformation can produce similar spectral displacement. Here, spherical Au and Ag reference particles are used to compare these mechanisms with the Discrete Dipole Scattering code (DDSCAT), spatial-resolution and polarizability checks, and exact coated-sphere Mie benchmarks. The Au bulk-index calibration gave an endpoint sensitivity of approximately 176 nm per refractive-index unit (RIU). A 5 nm protein-like shell with refractive index 1.45 produced a 4.42 nm shift, equivalent to an apparent 0.0250 RIU change; a 10 nm shell produced an 8.38 nm shift and 0.0475 RIU. For a 30 nm-radius Ag core in water, the corrected Bennett et al. composite tarnish-film model gave exact-Mie shifts of 15.31, 33.27 and 48.24 nm for 1–3 nm shells. At 3 nm, the full width at half maximum (FWHM) increased from 48.14 to 81.50 nm, the quality factor (Q) decreased from 8.67 to 5.71, the scattering fraction decreased from 85.23% to 55.27%, and the physical peak extinction cross-section decreased by 17.96%. DDSCAT resolution and polarizability checks preserved these trend directions while bounding their numerical sensitivity. Peak displacement alone was therefore not mechanism-specific. Joint interpretation of wavelength, linewidth, Q, physical extinction cross-section and scattering–absorption partition provides a more defensible basis for separating sensing response from surface-related artifacts.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 8","pages":"3503 - 3513"},"PeriodicalIF":5.6,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149072388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Effective Electrosynthesis of Catalytic Active Nanocomposites of Silver and Palladium Nanoparticles with Porphyrins, Having an Ability to Bind Antitumor Drugs","authors":"Rezeda R. Fazleeva,&nbsp;Gulnaz R. Nasretdinova,&nbsp;Andrey A. Maslennikov,&nbsp;Irek R. Nizameev,&nbsp;Igor V. Yanilkin,&nbsp;Nina V. Biktanova,&nbsp;Aidar T. Gubaidullin,&nbsp;Albina Y. Ziganshina,&nbsp;Vitaliy V. Yanilkin","doi":"10.1007/s11468-026-03451-8","DOIUrl":"10.1007/s11468-026-03451-8","url":null,"abstract":"<div><p>Effective porphyrin-mediated electrosyntheses of nanocomposites of silver and palladium nanoparticles (AgNPs and PdNPs) with tetraphenylporphyrin (TPP), as well as its complex with cobalt(II) (TPPCo(II)) were carried out in the absence and presence of a stabilizer poly(N-vinylpyrrolidone) (PVP), in dimethylsulfoxide (DMSO) medium at room temperature. Silver or palladium ions were in situ generated directly during electrolysis by dissolving the corresponding metal anodes. The synthesis results were universal hybrid organo-inorganic nanocomposites of mainly spherical AgNPs and PdNPs, stabilized by the coordination interaction of pyrrole nitrogen atoms with metal(0) in the porphyrin matrix or by polymer PVP The X-ray photoelectron spectroscopy (XPS) of obtained samples also confirms a presence of metallic palladium as nanocomposite with porphyrin. The fluorescence spectroscopy study of the obtained nanocomposites ability to bind the antitumor drug doxorubicin (DOX) demonstrated the presence of almost 100% quenching of DOX fluorescence in the presence of all nanocomposites with palladium and 71% quenching in the presence of the Ag/TPPCo(II)@PVP composite. A study of the nanocomposites catalytic activity in the test reaction of <i>p</i>-nitrophenol (pNPh) reduction with sodium borohydride showed that all the studied nanocomposites had a catalytic activity comparable and even prevailing relative to the previously obtained results.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 9","pages":"3609 - 3632"},"PeriodicalIF":5.6,"publicationDate":"2026-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149078874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-Sensitivity Ge-Doped PCF-SPR Temperature Sensor Based on Au/TiO₂ Hyperbolic Metamaterial","authors":"Xu Gao,&nbsp;Honggang Pan,&nbsp;Xing Wang,&nbsp;Xinjie Zhao,&nbsp;Yating Tang","doi":"10.1007/s11468-026-03450-9","DOIUrl":"10.1007/s11468-026-03450-9","url":null,"abstract":"<div><p>A Ge-doped photonic crystal fiber (PCF) surface plasmon resonance (SPR) temperature sensor based on an Au/TiO₂ hyperbolic metamaterial (HMM) is proposed and numerically investigated. In the proposed structure, Ge-doped silica is introduced into the core region to enhance core-mode confinement and provide a stable basis for coupling with the surface plasmon polariton (SPP) mode. PDMS is employed as the temperature-sensitive material due to its large negative thermo-optic coefficient, while the Au/TiO₂ multilayer is used to construct an HMM interface for improving plasmonic coupling and resonance quality. The Au/TiO₂ HMM provides anisotropic permittivity modulation and tunable SPP dispersion, which enhances the field overlap between the core-guided mode and the plasmonic mode. The sensing mechanism is analyzed based on the phase matching between the core mode and the SPP mode. The effects of key structural parameters, including air-hole spacing, polishing depth, air-hole diameter, refractive index (RI) difference induced by Ge doping, HMM layer thickness, and period number, are systematically optimized. The optimized sensor exhibits a nonlinear temperature response over a wide temperature range from − 13 °C to 120 °C. A maximum wavelength sensitivity (WS) of 75 nm/°C is achieved in the low-temperature interval from − 13 °C to − 12 °C, while the average WS over the whole range is 4.96 nm/°C. The proposed sensor offers a compact optical-fiber platform for wide-range temperature detection with enhanced sensitivity in the low-temperature region.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 10","pages":"3853 - 3862"},"PeriodicalIF":5.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149176401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Serum-Responsive SERS-Machine Learning Platform for Predictive Monitoring of Anticancer 6-Mercaptopurine Using Smart Hydrogel: Kinetic Modeling and In-Silico Validation","authors":"Munawar Hussain,&nbsp;Arslan Younas,&nbsp;Salim Jamil,&nbsp;Hesham M. Hassan,&nbsp;Khalaf F. Alsharif,&nbsp;Fuad M. Alzahrani,&nbsp;Khalid J. Alzahrani,&nbsp;Arslan Ali","doi":"10.1007/s11468-026-03447-4","DOIUrl":"10.1007/s11468-026-03447-4","url":null,"abstract":"<div><p>Molecularly specific and predictive monitoring of anticancer drug release in human serum remains difficult using conventional single-readout analytical methods. In this research work, a serum-responsive SERS-machine learning platform was developed for predictive monitoring of 6-mercaptopurine (6-MP) release from OS/PVA/ZnO hydrogel in human blood serum. The study integrates SERS-based release tracking, chemometric discrimination, machine-learning prediction, UV-Vis validation, and in-silico interaction analysis to evaluate 6-MP in-vitro release from the OS/PVA/ZnO hydrogel in human serum. AgNPs-assisted SERS spectra were acquired over 4–36 h release intervals, where released 6-MP showed diagnostic bands at 579, 727, 961, 1042, 1168, 1372, 1512, and 1608 cm^− 1, mainly associated with purine-ring deformation, ring breathing, C-N/C-C skeletal vibrations, C = N/C-N stretching, and heteroaromatic ring-stretching modes. Time-dependent intensity changes confirmed progressive 6-MP release and provided spectral fingerprints for multivariate analysis. PCA and HCA revealed clear discrimination between serum and release intervals. PCA-SVM and PCA-KNN enabled classification of release stages, whereas SVR provided quantitative prediction of 6-MP release from SERS features which was validated by UV-Vis spectrophotometer analysis. Kinetic modeling showed the best fit with the Korsmeyer-Peppas model (R² = 0.9989, <i>n</i> = 0.48), followed by zero-order (R² = 0.9939), Higuchi (R² = 0.9537), and first-order (R² = 0.8814) models. Docking with human serum albumin (PDB ID: 1AO6) showed moderate binding affinity of -5.2 kcal/mol. This work demonstrates a uniquely integrated serum-phase analytical platform, developed for the simultaneous molecular fingerprinting, release-stage classification, and quantitative prediction of the hydrogel-released 6-MP, which is validated using UV-Vis, kinetic modeling, and exploratory HSA interaction analysis.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 9","pages":"3545 - 3566"},"PeriodicalIF":5.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149078869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Refractive Index Response of Square and Hexagonal Gold Nanoparticle Arrays in a Kretschmann LSPR Sensor","authors":"Ying Du,&nbsp;Long Xiao,&nbsp;Huanlun Zhu,&nbsp;Hailang Guo,&nbsp;Yuying Wang,&nbsp;Yifen Lian,&nbsp;Yizhou Zhang,&nbsp;Ming Zhang","doi":"10.1007/s11468-026-03439-4","DOIUrl":"10.1007/s11468-026-03439-4","url":null,"abstract":"<div><p>Localized surface plasmon resonance (LSPR) of close-packed gold nanoparticle (AuNP) arrays in the Kretschmann configuration offers an attractive platform for optical sensing owing to its high sensitivity, label-free operation, and real-time response. Both near-field enhancement and far-field optical responses are sensitive to variations in the organization of nanoscale AuNPs and their interparticle spacing. In this work, we systematically investigate the far-field spectra and sensing behavior of square- and hexagonally packed AuNPs with diameters ranging from 10 to 60 nm and interstitial spacings from 5 to 30 nm, using three-dimensional finite element modeling (FEM). To the best of our knowledge, this parameter range and coverage density constitute the first systematic exploration of array-based sensing under the Kretschmann configuration. Compared with square arrays, hexagonally packed AuNPs generate a higher density of interstitial hot spots along two interparticle axes under <i>p-polarized</i> incidence, corresponding to up to ~ 3-fold enhancement in near-field intensity. The increased electromagnetic coupling results in a ~ 70% increase in refractive index (RI) sensitivity for a given AuNP diameter and interparticle gap. Notably, the sensitivity enhancement with decreasing gap distance deviates from a monotonic trend in hexagonal arrays, challenging the conventional intuition that ‘the smaller the gap, the better’. This finding suggests the existence of an optimal gap window, which holds important guiding significance for process tolerance design and parameter selection in practical devices. An optimized AuNP array achieves the calculated RI sensitivity 363 nm/RIU with a figure of merit (FOM) 9.6 RIU^− 1.</p></div>","PeriodicalId":736,"journal":{"name":"Plasmonics","volume":"21 9","pages":"3633 - 3645"},"PeriodicalIF":5.6,"publicationDate":"2026-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11468-026-03439-4.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149078871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}