Results in Optics最新文献

{"title":"High-performance dual-band graphene absorbers in the near-infrared range","authors":"Shao-Yu Liu,&nbsp;Yuan-Jin Lin,&nbsp;Guo-Yu Li,&nbsp;Shih-Lun Chen,&nbsp;Wei-Chen Tu","doi":"10.1016/j.rio.2026.101087","DOIUrl":"10.1016/j.rio.2026.101087","url":null,"abstract":"<div><div>The inherent limitations of monolayer graphene, specifically its low optical absorption and lack of spectral selectivity, significantly restrict its application in advanced optoelectronic devices. To overcome these challenges, this study proposes a novel absorber structure consisting of metal, dielectric, and metal layers coupled with graphene. This configuration greatly enhances the interaction between incident light and the graphene material. Initially, two individual absorbers were designed for specific wavelengths and subsequently integrated into a comprehensive dual wavelength band structure. This integrated design achieves a total absorption rate exceeding 99% at both the 1 μm and 2 μm target wavelengths. Concurrently, the graphene layer specifically contributes 32.8% and 21.6% to the absorption at these respective wavelengths. To efficiently optimize complex structural variables, an iterative method was introduced, which drastically reduces the required computational effort. Ultimately, the proposed design boosts the absorption capability by a factor of 10 to 15 compared to bare monolayer graphene. This research provides a highly promising and efficient approach for developing high performance nanophotonic devices.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101087"},"PeriodicalIF":3.3,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148641399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optical and magnetic characteristics of rare-earth- Sm3+ ion substituted Cobalt nano crystalline ferrites for optoelectronic applications","authors":"Lakkoju Santosh Kumar ,&nbsp;K.V. Ramesh ,&nbsp;Davuluri Venkatesh","doi":"10.1016/j.rio.2026.101008","DOIUrl":"10.1016/j.rio.2026.101008","url":null,"abstract":"<div><div>This study comprehensively investigated the optical characteristics of samarium-doped cobalt nano-ferrites synthesized via sol–gel auto-combustion for optoelectronic applications. Structural analysis of the samples was performed using X-ray diffraction, which confirmed the formation of a spinel structure. The lattice constants increased with the addition of Sm³⁺ ions and were in the range of 8.3724 – 8.3810  Å. UV–Vis spectroscopy revealed that the direct optical bandgap varied between 2.211 and 2.331 eV, while the indirect bandgap ranged from 1.145 to 1.206 eV, confirming the semiconducting nature of the materials. Urbach energy measurements revealed lattice disorder effects. The transmittance, reflectance, extinction coefficient, and refractive index were evaluated to assess the potential of the optical devices. The samples exhibited complex refractive index behavior and optical permittivity, which are suitable for high-frequency applications. The optical conductivity and density peaked at 10% Sm doping. Surface plasmon effects were observed, with the quality factors decreasing at 15% doping due to quantum confinement. Magnetic measurements showed that the saturation magnetization (M_s) decreased from 46.76 to 38.92 emu/g, and the coercivity (H_c) varied between 1012 and 1186 Oe with the Sm³⁺ concentration. This was attributed to spin disorder, except for an anomalous increase of 15%, possibly due to the formation of a secondary phase. These results indicate that Sm³⁺ substitution effectively tunes both the optical and magnetic behaviors, making these ferrites promising materials for high-frequency, optoelectronic, and spintronic applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101008"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147652262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultra-broadband polarization-independent metamaterial absorber from UV-C to LWIR: design and optimization","authors":"Valiolah Pourhossein Bagheri ,&nbsp;Hamed Saghaei ,&nbsp;Alireza Ghorbani","doi":"10.1016/j.rio.2026.101012","DOIUrl":"10.1016/j.rio.2026.101012","url":null,"abstract":"<div><div>This study presents the design and optimization of a polarization-independent ultra-broadband metamaterial absorber operating over an exceptionally wide spectral span from 150 nm (UV-C) to 10,000 nm (long-wave infrared). The proposed unit cell integrates elliptical titanium (Ti) and aluminum oxide (Al₂O₃) resonators with a multilayer stack composed of chromium (Cr), silicon monoxide (SiO), and iron (Fe), enabling strong plasmonic resonances, enhanced impedance matching, and efficient electromagnetic energy confinement across ultraviolet, visible, near-infrared, and infrared bands. A particle swarm optimization framework was employed to refine the geometric parameters via systematic parameter sweeps and an iterative global search, aiming to maximize the average absorptance over the full wavelength range. Numerical simulations based on the finite-difference time-domain method show that the optimized structure achieves an average absorption of 96.82% via stepwise optimization and 97.12% via simultaneous multi-parameter optimization, representing a substantial enhancement relative to the initial pre-optimized baseline of 86.09%. Electric- and magnetic-field distribution analyses reveal pronounced plasmonic hot-spot formation at metal–dielectric interfaces and confirm stable polarization-insensitive performance under both TE and TM excitations, consistent with the nearly overlapping absorption spectra for the two polarization states. Owing to its ultra-wide spectral coverage and robust polarization independence, the proposed absorber is a promising platform for broadband solar energy harvesting, multispectral sensing, thermal imaging, and infrared energy management.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101012"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147652263","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural, magnetic and optical properties of functionally tailored TiO2 nanoparticles","authors":"Sanjay Kumar ,&nbsp;Virendra Kumar ,&nbsp;Manoj Kumar Bansal ,&nbsp;Arvind Mishra ,&nbsp;Chandra Shakher Pathak","doi":"10.1016/j.rio.2026.101016","DOIUrl":"10.1016/j.rio.2026.101016","url":null,"abstract":"<div><div>We report Pristine TiO₂ (Titanium dioxide) and synthesis of its doped variants with Mn and Fe i.e. Ti_0.98Mn_0.02 (manganese doped Titanium dioxide) and Ti_0.98Fe_0.02 (iron doped Titanium dioxide) by solid-state reaction method in this study. The experiments were sintered at temperature 500 °C. Without the production of any impurity phases, X-ray diffraction investigations show the formation of the anatase phase of TiO₂ fitting to the 141/amd space set in both samples. The crystal structure does not change when 2% Mn content is added, revealing the precise replacement of Mn &amp; Fe atoms at their locations. The variation in ionic radii is responsible for some of the observed changes in lattice characteristics and crystallite dimension in Mn &amp; Fe-doped structures. The size of the crystallites as determined by X-ray diffraction analysis is comparable with the grain size as determined by scanning electron micrographs. The integration of Mn and Fe content in the TiO₂ structure has been verified by energy-dispersive X-ray analysis. Ferromagnetic behavior found in Mn and Fe-doped TiO₂ composition is consistent with the significant contribution of the Mn d-shell. The field of electric polarization (P–E) have a very low energy loss, according to hysteresis loops. The findings demonstrate that the sintering temperature and atmosphere had a significant impact on the magnetic properties.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101016"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147652264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Defect-driven photoluminescence quenching in WO3 micro-flakes: a simple approach for bisphenol A detection","authors":"Hamood Al Shidhani ,&nbsp;Basim Al Farsi ,&nbsp;R.G. Sumesh Sofin ,&nbsp;Faisal Al Marzouqi ,&nbsp;Zainab B. Al-Ruqaishi ,&nbsp;Abey Issac ,&nbsp;Osama K Abou-Zied ,&nbsp;Mohammed Z. Al-Abri ,&nbsp;S.R. Sirasanagandla","doi":"10.1016/j.rio.2026.101020","DOIUrl":"10.1016/j.rio.2026.101020","url":null,"abstract":"<div><div>Accurate and simple detection of environmentally hazardous molecules such as bisphenol A (BPA) remains a significant challenge in optical sensing. This study presents a novel approach utilizing photoluminescence (PL) spectroscopy of tungsten trioxide (WO₃) micro-flakes synthesized via a solution-phase route, with enhanced sensitivity achieved through controlled annealing. The annealing process at 350 °C under low vacuum induces a phase transition from orthorhombic to monoclinic structure and increases oxygen vacancy concentrations, which are direction dependent within the crystal lattice. These vacancies act as emission centers, whose PL response is modulated by BPA concentrations, resulting in measurable quenching effects. Theoretical predictions of charge transition levels (CTLs) identify the key emission centers responsible for the observed optical behavior. The method achieves a detection limit of 0.025 μmol/L, demonstrating sensitivity comparable to other complex analytical techniques, while offering advantages in simplicity and real-time monitoring. The underlying quenching mechanism involves electron transfer from oxygen vacancies to BPA’s H⁺ ions, confirming a static quenching pathway. The present work primarily demonstrates the feasibility of defect-engineered WO₃ as a model optical transducer for BPA through a vacancy-mediated quenching mechanism, that can serve as a foundation for future selectivity and real-sample studies. This work advances optical sensing by coupling crystal structure engineering with PL spectroscopy, providing an efficient and practical platform for environmental and health monitoring of biohazardous molecules.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101020"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147799028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a high-accuracy optical model of red phosphor and its application in improving the color rendering index of phosphor converted white laser lighting applications","authors":"Duy-Nhat Le ,&nbsp;Ai Than ,&nbsp;Quoc-Cuong Nguyen ,&nbsp;Vo-Hoang-Phuc Nguyen ,&nbsp;Van-Tuan Huynh ,&nbsp;Nguyet-Thuan Phan ,&nbsp;Chi-Linh Nguyen ,&nbsp;Anh-Thu Nguyen ,&nbsp;Huynh-Tuan Anh Nguyen ,&nbsp;Hoai-Trung Dang ,&nbsp;Quang-Khoi Nguyen","doi":"10.1016/j.rio.2026.101052","DOIUrl":"10.1016/j.rio.2026.101052","url":null,"abstract":"<div><div>We reported a high-accuracy optical model for improving the color rendering index of white light in laser lighting applications. White light is generated by using a blue laser to excite the yellow phosphor. The color rendering index of white light is improved by adding different amounts of red-light content. Also, the effect of added red light on the optical and chromaticity properties is investigated. The accuracy of the optical model is verified with normalized cross-correlation algorithms. The NCC value is 99.82% at beta value 3.0 indicating the trustable of developed spectrum model. Also, the application of spectrum modeling of red light is investigated for the case of blue laser-based phosphor converted white light. The initial CRI of 58 is significantly enhanced to 82 as the added red-light power of 1.5, 1.6, 1.7, 1.8, 1.9, respectively. Adding different power of red emission band on white light spectrum helps to ensure the allowable distance to the Planckian locus curve (e.g. color point error less than 0.005). Experiment results confirmed the high CRI of 85 is obtained compare to initial CRI of 60 after modifying the red-light power in the white spectrum by combining red phosphor and yellow phosphor.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101052"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148167803","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relative illumination engineering of near infrared metalens based on mixed-pitch meta-atom","authors":"Qiu-Chun Zeng ,&nbsp;Chen-Yi Yu ,&nbsp;Wei-Lun Hsu ,&nbsp;Yen-Chun Chen ,&nbsp;You-Song Huang ,&nbsp;Cheng-Yu Li ,&nbsp;Guo-Hao Lu ,&nbsp;Chun-Jen Weng ,&nbsp;Fong-Zhi Chen ,&nbsp;Wei-Cheng Lin ,&nbsp;Che-Chin Chen ,&nbsp;Chih-Ming Wang","doi":"10.1016/j.rio.2026.101053","DOIUrl":"10.1016/j.rio.2026.101053","url":null,"abstract":"<div><div>We present and compare three metalens configurations, telecentric, non-telecentric, and telecentric with a mixed-pitch design, optimized for 940 nm operation with a 120° field of view. Comprehensive evaluation of modulation transfer function, distortion, and relative illumination (RI) reveals distinct trade-offs in performance. The telecentric design achieves the highest image quality but suffers from higher distortion and reduced RI. The non-telecentric design minimizes distortion and cost, though at the expense of resolution. By using the relative illumination uniform engineering, the mixed-pitch design offers a balanced solution, enhancing edge resolution and RI (up to 87% @ FoV = 45°), making it well-suited for wide-angle, high-performance imaging. This study provides design guidelines for tailoring metalenses to application-specific needs.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101053"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148167805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-sensitivity plasmonic glucose sensor based MIM –waveguide with a drop cavity and ring resonator for industrial applications","authors":"Hengameh Farokhi,&nbsp;Sedighe BabaeiSedaghat","doi":"10.1016/j.rio.2026.101032","DOIUrl":"10.1016/j.rio.2026.101032","url":null,"abstract":"<div><div>A novel metal–insulator–metal (MIM) plasmonic sensor has been designed and numerically optimized for highly sensitive detection of glucose concentration via refractive index (RI) modulation. The proposed structure consists of a compact MIM bus waveguide side-coupled to a composite cavity formed by a drop-shaped cavity embedded within an opened ring resonator. This configuration enables the generation of multiple coupled resonance modes with strong electromagnetic field confinement, enhancing light–matter interaction in the sensing region and providing an effective approach for engineering multi-resonance plasmonic responses in compact MIM sensors. Through comprehensive geometric optimization- nine key structural parameters- such as coupling gap, drop-shape cavity dimensions, and ring configuration- were identified as critical factors in enhancing both sensitivity and spectral characteristics. The optimized sensor exhibits multiple sharp resonance modes in the near-infrared region (NIR), with strong electromagnetic field confinement observed within the cavity. Numerical results reveal a high refractive index (RI) sensitivity of <span><math><mrow><mn>1296.7</mn><mi>n</mi><mi>m</mi><mo>/</mo><mi>R</mi><mi>I</mi><mi>U</mi></mrow></math></span> for the optimized mode. For refractive index sensing, the calculated Q factors for the two main modes are 41.27 and 24.73, while the corresponding FOM values are 38.46 RIU⁻¹ and 21.43 RIU⁻¹, with LOD values on the order of 10⁻⁶ RIU. By incrementally varying glucose concentration and converting the values to their corresponding refractive indices, a linear and robust wavelength shift response was achieved, yielding a sensitivity of 0.1857 (nm.L)/g over the concentration range of (0–200 g/L). The proposed plasmonic glucose sensor operates over a wide concentration range, enabling real-time monitoring in industrial applications. Its performance surpasses several recent MIM-based sensors, highlighting the effectiveness of the presented multi-resonance design and the importance of precise geometric engineering in high–performance plasmonic sensors.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101032"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147952186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of a reconfigurable two-dimensional photonic crystal filter and sensor for biomedical and industrial applications","authors":"Abhishek Singh ,&nbsp;Shivin Kumar ,&nbsp;J. Divya ,&nbsp;Selvendran S","doi":"10.1016/j.rio.2026.101043","DOIUrl":"10.1016/j.rio.2026.101043","url":null,"abstract":"<div><div>This study presents the design of a novel two-dimensional (2D) photonic crystal (PhC)-based reconfigurable filter and sensor. A systematic approach was employed to design periodic structures with tailored optical properties by manipulating refractive indices and introducing strategic defects. The proposed silicon PhC structure, featuring air holes with a radius of 0.26 µm, exhibits a photonic band gap (PBG) spanning 1.85 µm to 2.55 µm. The compact and multifunctional structure can perform both optical filtering and refractive index (RI) sensing within the same photonic crystal configuration through a defect-engineered approach. Optimized structural parameters enabled the filter to achieve a transmissivity of 59.33% with a quality factor (Q-factor) of approximately 71.88 at a resonant cavity air hole radius of 0.245 µm. Furthermore, the device demonstrates high sensitivity to RI variations in the range of 1.0 to 1.35 within the resonant cavity air holes (R1 and R2), with a maximum observed sensitivity of 106 nm/RIU. With compact dimensions of 3.92 µm × 2.92 µm, the design provides a versatile framework for PhC-based sensing and filtering applications. These capabilities make it highly suitable for biomedical diagnostics, industrial chemical analysis, and optical communication systems, offering a scalable and efficient solution for diverse advanced applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101043"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147991579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A comprehensive study on indoor VLC systems using advanced equalization techniques employing CAP modulation in SISO, SMP, and SM configurations","authors":"Saeed Ashouri,&nbsp;Gholamreza Baghersalimi,&nbsp;Hossein Goorani","doi":"10.1016/j.rio.2026.101033","DOIUrl":"10.1016/j.rio.2026.101033","url":null,"abstract":"<div><div>Indoor visible light communication (VLC) using light-emitting diodes (LEDs) faces critical performance challenges due to LED nonlinearity, limited modulation bandwidth, and multipath-induced inter-symbol interference. This study evaluates carrierless amplitude and phase (CAP) modulation across single-input single-output (SISO), spatial multiplexing (SMP), and spatial modulation (SM) configurations, employing linear least mean square (LMS) and nonlinear Legendre functional link artificial neural network (Le-FLANN) and Volterra equalization techniques. Under realistic LED operating conditions and spatial misalignment, Le-FLANN achieves significant signal-to-noise-ratio per bit (<em>E</em>_b/<em>N</em>₀) improvements at bit error rate (BER) = 10⁻⁴: 0.9 dB in SISO, 2.9 dB in SMP, and 1.5 dB in SM, compared to LMS. SMP delivers an aggregate throughput of 24 Mbps by transmitting two independent 12 Mbps CAP streams in parallel over a 4.5 MHz LED bandwidth. These findings demonstrate the practical value of structured nonlinear equalization in bandwidth-constrained VLC links, offering enhanced resilience to LED-induced distortion and spatial channel impairments.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"24 ","pages":"Article 101033"},"PeriodicalIF":3.0,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147991580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}