Pub Date : 2026-02-01Epub Date: 2025-11-24DOI: 10.1016/j.ijleo.2025.172612
Ghobad Mohammad Karimi , Mohammad Azim Karami , Hassan Ghalami Bavil Olyaee , Javad Karamdel
In this paper, The fundamental characteristic such as electronic and optical properties of silicon carbide nanosheets (3,3) are investigated using the density functional theory (DFT) by including defects and impurity dopings. In addition to the perfect layer analysis, four defect types are considered: one vacancy of silicon atom, one vacancy of carbon atom, two vacancies of atoms (a combined silicon and carbon vacancy) and Stone-Wales defect. Moreover, impurity doping effect for two perfect layers are studied, with each layer doped separately with a single nitrogen and molybdenum atom. The bandgap of the pristine layer was determined to be 2.82 eV, and simulation results indicate that the band gap significantly decreases by defect introduction, whereas the introduction of impurity doping results in only a slight reduction in the band gap. The layer with nitrogen doping exhibits the highest absorption coefficient, while the layer with a double carbon and silicon defect shows the lowest absorption coefficient.
{"title":"Electronic and optical properties of silicon carbide nanosheets (3,3) including defects and impurity dopings","authors":"Ghobad Mohammad Karimi , Mohammad Azim Karami , Hassan Ghalami Bavil Olyaee , Javad Karamdel","doi":"10.1016/j.ijleo.2025.172612","DOIUrl":"10.1016/j.ijleo.2025.172612","url":null,"abstract":"<div><div>In this paper, The fundamental characteristic such as electronic and optical properties of silicon carbide nanosheets (3,3) are investigated using the density functional theory (DFT) by including defects and impurity dopings. In addition to the perfect layer analysis, four defect types are considered: one vacancy of silicon atom, one vacancy of carbon atom, two vacancies of atoms (a combined silicon and carbon vacancy) and Stone-Wales defect. Moreover, impurity doping effect for two perfect layers are studied, with each layer doped separately with a single nitrogen and molybdenum atom. The bandgap of the pristine layer was determined to be 2.82 eV, and simulation results indicate that the band gap significantly decreases by defect introduction, whereas the introduction of impurity doping results in only a slight reduction in the band gap. The layer with nitrogen doping exhibits the highest absorption coefficient, while the layer with a double carbon and silicon defect shows the lowest absorption coefficient.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172612"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-10-31DOI: 10.1016/j.ijleo.2025.172585
Feifan Li , Yongmo Lv , Chen Wang , Jianting Fu , Hengqing Cui , Jun Shen , Haibo Jiang , Shaoyun Yin
Existing holographic speckle diffusers are limited by the speckle exposure method, which can only achieve circular or elliptical scattering light patterns. In this paper, based on the mechanism that the scattered light pattern of a holographic diffuser is determined by its recorded spatial frequency spectrum (SFS) of the speckle field, a frequency spectrum modulation system for the preparation of holographic diffuser is proposed and designed. By precisely controlling the SFS of the speckle field, holographic diffusers capable of producing scattered light patterns such as squares, diamonds, hexagons, etc. have been prepared. The method proposed in this paper addresses the preparation of holographic speckle diffusers for complex scattered light patterns, which is expected to broaden the application areas of holographic diffusers further.
{"title":"Holographic speckle diffusers with complex scattered beam patterns realized by using a frequency spectrum modulation system","authors":"Feifan Li , Yongmo Lv , Chen Wang , Jianting Fu , Hengqing Cui , Jun Shen , Haibo Jiang , Shaoyun Yin","doi":"10.1016/j.ijleo.2025.172585","DOIUrl":"10.1016/j.ijleo.2025.172585","url":null,"abstract":"<div><div>Existing holographic speckle diffusers are limited by the speckle exposure method, which can only achieve circular or elliptical scattering light patterns. In this paper, based on the mechanism that the scattered light pattern of a holographic diffuser is determined by its recorded spatial frequency spectrum (SFS) of the speckle field, a frequency spectrum modulation system for the preparation of holographic diffuser is proposed and designed. By precisely controlling the SFS of the speckle field, holographic diffusers capable of producing scattered light patterns such as squares, diamonds, hexagons, etc. have been prepared. The method proposed in this paper addresses the preparation of holographic speckle diffusers for complex scattered light patterns, which is expected to broaden the application areas of holographic diffusers further.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172585"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-11-20DOI: 10.1016/j.ijleo.2025.172611
Wende Dong , Tianheng Xu , Muhan Ji , Gang Luo , Geng Li , Zhenzhen Zheng
In hazy weather, suspended particles in the air cause significant image degradation by attenuating and scattering light. This degradation poses substantial challenges to subsequent image processing tasks, such as target recognition and positioning. Existing methods often struggle to balance global atmospheric light estimation with fine-detail preservation, leading to residual haze or over-enhancement and color distortion. Inspired by attention mechanisms, we design a hazy image restoration architecture utilizing an improved U-Net based generative adversarial network (GAN), enhanced by a novel hybrid attention mechanism. This mechanism integrates a global attention modulator, a window-based multi-head self-attention module, and a locally enhanced feedforward network, enabling the model to effectively capture both global and local image features while mitigating the artifacts seen in prior work. The network is trained using a tailored loss function that combines pixel loss, adversarial loss, and edge loss, specifically designed for the image dehazing task. Extensive experiments conducted on synthetic and real hazy images demonstrate that the proposed method consistently delivers high-quality dehazed images with exceptional clarity and contrast, outperforming several state-of-the-art methods.
{"title":"Hybrid self-attention aided generative adversarial network for hazy image restoration","authors":"Wende Dong , Tianheng Xu , Muhan Ji , Gang Luo , Geng Li , Zhenzhen Zheng","doi":"10.1016/j.ijleo.2025.172611","DOIUrl":"10.1016/j.ijleo.2025.172611","url":null,"abstract":"<div><div>In hazy weather, suspended particles in the air cause significant image degradation by attenuating and scattering light. This degradation poses substantial challenges to subsequent image processing tasks, such as target recognition and positioning. Existing methods often struggle to balance global atmospheric light estimation with fine-detail preservation, leading to residual haze or over-enhancement and color distortion. Inspired by attention mechanisms, we design a hazy image restoration architecture utilizing an improved U-Net based generative adversarial network (GAN), enhanced by a novel hybrid attention mechanism. This mechanism integrates a global attention modulator, a window-based multi-head self-attention module, and a locally enhanced feedforward network, enabling the model to effectively capture both global and local image features while mitigating the artifacts seen in prior work. The network is trained using a tailored loss function that combines pixel loss, adversarial loss, and edge loss, specifically designed for the image dehazing task. Extensive experiments conducted on synthetic and real hazy images demonstrate that the proposed method consistently delivers high-quality dehazed images with exceptional clarity and contrast, outperforming several state-of-the-art methods.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172611"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-11-17DOI: 10.1016/j.ijleo.2025.172602
Rusul A. Dahab, Hussein A. Jawad
Optical losses represent one of the primary obstacles to increasing the efficiency of silicon solar cells. The recommended solution to minimize optical losses is the use of plasmonic metal nanoparticles; however, they act as recombination centers within the solar cell construction, leading to a decrease in performance. The goal of this article is to introduce cobalt/graphene nanoparticles into the solar cell to minimize the optical losses. An ultra-thin film silicon PIN solar cell of dimensions (400 ×400 ×900) nm3 with ring metal contact shape was designed and numerically investigated using COMSOL Multiphysics software version 6.2 by the finite element method (FEM). Core/shell cobalt-graphene (Co/Gr) nanoparticles are periodically introduced into the cell between two layers (electron transport and active) in a ratio of 50:50 with an inter-spacing of a similar diameter. The Co/Gr parameters, number of nanoparticles (2, 4, 6), radius (10, 20, 30) nm, and shell thickness (1, 2, 4) nm were extensively studied. In addition, the arrangement of the core/shell nanoparticle material was considered. The results manifest the best performance of the proposed cell at 4 nanoparticles of 30 nm radius with 2 nm shell thickness for Co/Gr nanoparticles to get a maximum photocurrent of 26.28 mA/cm2. It is concluded that the optical losses of the Co/Gr core/shell nanoparticles embedded in an ultra-thin film silicon solar cell are significantly reduced owing to the increment in the absorption and hence the photocurrent. This enhancement opens a new avenue for further improvements.
{"title":"Mitigation optical losses via plasmonic core/shell (Co/Gr) nanoparticles introduced in ultra-thin film silicon solar cell","authors":"Rusul A. Dahab, Hussein A. Jawad","doi":"10.1016/j.ijleo.2025.172602","DOIUrl":"10.1016/j.ijleo.2025.172602","url":null,"abstract":"<div><div>Optical losses represent one of the primary obstacles to increasing the efficiency of silicon solar cells. The recommended solution to minimize optical losses is the use of plasmonic metal nanoparticles; however, they act as recombination centers within the solar cell construction, leading to a decrease in performance. The goal of this article is to introduce cobalt/graphene nanoparticles into the solar cell to minimize the optical losses. An ultra-thin film silicon PIN solar cell of dimensions (400 ×400 ×900) nm<sup>3</sup> with ring metal contact shape was designed and numerically investigated using COMSOL Multiphysics software version 6.2 by the finite element method (FEM). Core/shell cobalt-graphene (Co/Gr) nanoparticles are periodically introduced into the cell between two layers (electron transport and active) in a ratio of 50:50 with an inter-spacing of a similar diameter. The Co/Gr parameters, number of nanoparticles (2, 4, 6), radius (10, 20, 30) nm, and shell thickness (1, 2, 4) nm were extensively studied. In addition, the arrangement of the core/shell nanoparticle material was considered. The results manifest the best performance of the proposed cell at 4 nanoparticles of 30 nm radius with 2 nm shell thickness for Co/Gr nanoparticles to get a maximum photocurrent of 26.28 mA/cm<sup>2</sup>. It is concluded that the optical losses of the Co/Gr core/shell nanoparticles embedded in an ultra-thin film silicon solar cell are significantly reduced owing to the increment in the absorption and hence the photocurrent. This enhancement opens a new avenue for further improvements.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172602"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145546588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-12-01DOI: 10.1016/j.ijleo.2025.172632
Geetanjali Singla , Rashbha Sharma , Rajesh Khanna , Ashish Kumar , A. J.A. Al-Gburi
This paper presents a wideband dual-element flexible metasurface MIMO antenna (f-meta MIMO antenna), using TCM (Theory of Characteristic Modes) optimized metasurface of double-negative (DNG) metamaterial unit cells placed within a slotted rectangular patch. It resonates over a wide bandwidth of 2700 MHz (3.3–6.0 GHz) covering multiple sub-6 GHz bands. It is an extended design of single element flexible metasurface antenna designed on a 0.4 mm flexible sheet of FR-4 substrate achieving a bandwidth of 1000 MHz (3.1–4.1 GHz) in the sub-6 GHz range. A key novelty of this work is that the f-meta MIMO antenna elements maintain a high isolation (S12 > 19 dB) at a very small inter-element gap of 0.003 λ (λ corresponding to 3.35 GHz), without employing any additional isolation enhancement techniques. Furthermore, the f-meta MIMO demonstrates excellent diversity performance, including a low envelope correlation coefficient (< 0.05), high diversity gain (≈ 10 dB), high efficiency (> 85 %), a mean effective gain < −3 dB, and a total active reflection coefficient < −10 dB across the operating bandwidth. In addition, under several bending scenarios, the antenna maintains its compact volume (700 mm³) and preserves multiband operation with high isolation (S12 > 15 dB). This makes the antenna suitable for various 5 GHz applications such as 5 G NR, Wi-Fi and conformal applications such as V2X/ UAV terminals, wearable/ IoT devices.
{"title":"Design of a flexible, highly isolated multiband f-meta MIMO antenna for 5G sub-6 GHz applications using the theory of characteristic modes","authors":"Geetanjali Singla , Rashbha Sharma , Rajesh Khanna , Ashish Kumar , A. J.A. Al-Gburi","doi":"10.1016/j.ijleo.2025.172632","DOIUrl":"10.1016/j.ijleo.2025.172632","url":null,"abstract":"<div><div>This paper presents a wideband dual-element flexible metasurface MIMO antenna (f-meta MIMO antenna), using TCM (Theory of Characteristic Modes) optimized metasurface of double-negative (DNG) metamaterial unit cells placed within a slotted rectangular patch. It resonates over a wide bandwidth of 2700 MHz (3.3–6.0 GHz) covering multiple sub-6 GHz bands. It is an extended design of single element flexible metasurface antenna designed on a 0.4 mm flexible sheet of FR-4 substrate achieving a bandwidth of 1000 MHz (3.1–4.1 GHz) in the sub-6 GHz range. A key novelty of this work is that the f-meta MIMO antenna elements maintain a high isolation (S12 > 19 dB) at a very small inter-element gap of 0.003 λ (λ corresponding to 3.35 GHz), without employing any additional isolation enhancement techniques. Furthermore, the f-meta MIMO demonstrates excellent diversity performance, including a low envelope correlation coefficient (< 0.05), high diversity gain (≈ 10 dB), high efficiency (> 85 %), a mean effective gain < −3 dB, and a total active reflection coefficient < −10 dB across the operating bandwidth. In addition, under several bending scenarios, the antenna maintains its compact volume (700 mm³) and preserves multiband operation with high isolation (S12 > 15 dB). This makes the antenna suitable for various 5 GHz applications such as 5 G NR, Wi-Fi and conformal applications such as V2X/ UAV terminals, wearable/ IoT devices.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172632"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-11-19DOI: 10.1016/j.ijleo.2025.172604
Sanjeev Mani Yadav
{"title":"Corrigendum to “A novel PCF-based optical sensor: Design and modeling for early malaria detection” [Optik 342–343, December 2025, 172581]","authors":"Sanjeev Mani Yadav","doi":"10.1016/j.ijleo.2025.172604","DOIUrl":"10.1016/j.ijleo.2025.172604","url":null,"abstract":"","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172604"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145839218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-11-20DOI: 10.1016/j.ijleo.2025.172609
Yongkang Yang , Baiang Qu , Hongjie Xu , Manqing Tan , Wentao Guo
The amplified spontaneous emission (ASE) source is widely used in fiber-optic gyroscopes due to its broadband spectrum, which suppresses backscattering- and Kerr-effect–induced phase errors while reducing polarization coupling noise. However, thermally induced wavelength drift remains a critical limitation in ultrahigh-precision systems, as even small spectral shifts introduce non-negligible phase noise. To address this challenge, we propose a wide-temperature wavelength-selective reflection strategy that integrates a wavelength-division multiplexer, optical filter, and reflector into a compact hybrid structure, achieving a mean drift rate below 0.1 ppm/°C across the full operational range. This work presents a significant advance in ASE source technology through the integration of dual fiber Bragg gratings (FBGs) at the 974 nm laser diode (LD) output and a monolithically packaged passive-component module. Comprehensive theoretical modeling and experimental characterization of LD–ASE spectral–power correlations enabled the development of a thermally optimized dual-pass architecture achieving three major performance breakthroughs: (1) ultra-stable wavelength performance with drift below 0.1 ppm/°C over –25°C to + 60°C, (2) ASE output power above 25 mW with < 5 % variation across the temperature cycle, and (3) a record-high optical conversion efficiency exceeding 20 %. These results establish new performance benchmarks for ASE sources used in ultrahigh-precision fiber-optic gyroscopes operating under extreme environmental conditions. The dual-FBG wavelength-stabilization method and hybrid integrated architecture effectively address long-standing challenges in maintaining spectral purity and power efficiency under thermal stress, marking a substantial advancement in photonic light-source technology for precision inertial navigation.
{"title":"High-power wavelength-stabilized amplified spontaneous emission source enabled by 974 nm LD and hybrid integration","authors":"Yongkang Yang , Baiang Qu , Hongjie Xu , Manqing Tan , Wentao Guo","doi":"10.1016/j.ijleo.2025.172609","DOIUrl":"10.1016/j.ijleo.2025.172609","url":null,"abstract":"<div><div>The amplified spontaneous emission (ASE) source is widely used in fiber-optic gyroscopes due to its broadband spectrum, which suppresses backscattering- and Kerr-effect–induced phase errors while reducing polarization coupling noise. However, thermally induced wavelength drift remains a critical limitation in ultrahigh-precision systems, as even small spectral shifts introduce non-negligible phase noise. To address this challenge, we propose a wide-temperature wavelength-selective reflection strategy that integrates a wavelength-division multiplexer, optical filter, and reflector into a compact hybrid structure, achieving a mean drift rate below 0.1 ppm/°C across the full operational range. This work presents a significant advance in ASE source technology through the integration of dual fiber Bragg gratings (FBGs) at the 974 nm laser diode (LD) output and a monolithically packaged passive-component module. Comprehensive theoretical modeling and experimental characterization of LD–ASE spectral–power correlations enabled the development of a thermally optimized dual-pass architecture achieving three major performance breakthroughs: (1) ultra-stable wavelength performance with drift below 0.1 ppm/°C over –25°C to + 60°C, (2) ASE output power above 25 mW with < 5 % variation across the temperature cycle, and (3) a record-high optical conversion efficiency exceeding 20 %. These results establish new performance benchmarks for ASE sources used in ultrahigh-precision fiber-optic gyroscopes operating under extreme environmental conditions. The dual-FBG wavelength-stabilization method and hybrid integrated architecture effectively address long-standing challenges in maintaining spectral purity and power efficiency under thermal stress, marking a substantial advancement in photonic light-source technology for precision inertial navigation.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172609"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145570772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-11-20DOI: 10.1016/j.ijleo.2025.172610
Iman Razmkhah, Zahra Adelpour, Mojtaba Sadeghi
In this work, we present a novel compact plasmonic dual-band bandpass filter based on graphene nanoribbons, tunable through azo-dye-doped liquid crystal and graphene conductivity. Graphene nanoribbons are deposited on a silica substrate and covered with azo-dye-doped liquid crystal. Therefore, the performance of the plasmonic structure can be tuned by a laser pump and the graphene chemical potential. Full-wave simulations are performed in COMSOL Multiphysics using the Finite Element Method (FEM). In addition, Transmission Line Modelling and Electromagnetic Scaling Law are used to validate the numerical simulation results. The proposed filter resonates at 2.45 THz and 9.2 THz when the laser pump is off. However, when the laser pump is on, the resonant frequencies redshift to 2.3 THz and 8.6 THz. The corresponding quality factors are 20 and 31 for the lower and higher resonance frequencies when the laser pump is off. The simulated reflection coefficients (S₁₁) reach −31 dB and −38 dB for the two passbands confirming efficient transmission (S₂₁≈ 0 dB). The effect of graphene chemical potential and geometric variations on our structure is investigated. Finally, the size and performance of our filter are compared with the previously reported designs, demonstrating both practical feasibility and compactness. With a compact footprint of 420 × 350 nm2 and dual-band tunability, the proposed filter is a promising candidate for terahertz sensing and communication systems.
{"title":"The design and TLM analysis of a compact graphene-based dual-band bandpass plasmonic filter with hybrid post-fabrication tunability via liquid crystal in the terahertz regime","authors":"Iman Razmkhah, Zahra Adelpour, Mojtaba Sadeghi","doi":"10.1016/j.ijleo.2025.172610","DOIUrl":"10.1016/j.ijleo.2025.172610","url":null,"abstract":"<div><div>In this work, we present a novel compact plasmonic dual-band bandpass filter based on graphene nanoribbons, tunable through azo-dye-doped liquid crystal and graphene conductivity. Graphene nanoribbons are deposited on a silica substrate and covered with azo-dye-doped liquid crystal. Therefore, the performance of the plasmonic structure can be tuned by a laser pump and the graphene chemical potential. Full-wave simulations are performed in COMSOL Multiphysics using the Finite Element Method (FEM). In addition, Transmission Line Modelling and Electromagnetic Scaling Law are used to validate the numerical simulation results. The proposed filter resonates at 2.45 THz and 9.2 THz when the laser pump is off. However, when the laser pump is on, the resonant frequencies redshift to 2.3 THz and 8.6 THz. The corresponding quality factors are 20 and 31 for the lower and higher resonance frequencies when the laser pump is off. The simulated reflection coefficients (S₁₁) reach −31 dB and −38 dB for the two passbands confirming efficient transmission (S₂₁≈ 0 dB). The effect of graphene chemical potential and geometric variations on our structure is investigated. Finally, the size and performance of our filter are compared with the previously reported designs, demonstrating both practical feasibility and compactness. With a compact footprint of 420 × 350 nm<sup>2</sup> and dual-band tunability, the proposed filter is a promising candidate for terahertz sensing and communication systems.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172610"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145681839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-02-01Epub Date: 2025-11-27DOI: 10.1016/j.ijleo.2025.172622
Milan S. Kovačević , Vladimir Marković , Daniele Tosi , Wilfried Blanc , Ivona Kovačević , Ljubica Kuzmanović
This study presents a method for detecting cancer cells in human skin using a fiber-based sensor, referred to as a semi-distributed Fabry–Pérot interferometer (SDI FP sensor). The sensor employs a multimirror Fabry–Pérot structure formed between a single-mode cleaved fiber tip and a high-scattering fiber, whose core is doped with magnesium silicate nanoparticles, placed in contact with the three principal skin layers: epidermis, dermis, and hypodermis. For the first time, human skin is represented as a four-mirror Fabry–Pérot interferometer, with epidermal refractive index and thickness varying in the presence of cancer cells. First, the reflected spectrum of healthy skin tissue is modeled in the infrared wavelength range. Next, alterations in the reflected spectrum are analyzed in the presence of cancer cells, considering their distribution within each skin layer individually. The results reveal distinct shifts in spectral peaks and valleys between healthy and cancerous tissues, demonstrating the potential of the proposed approach for noninvasive detection of cancer cells across different skin layers. Additionally, a more sophisticated model was considered in which the epidermal refractive index varies randomly due to the presence of cancer cells, reflecting the realistic nonuniform distribution of cancer cells within the epidermal tissue. The proposed model provides a solid theoretical foundation for subsequent experimental validation
{"title":"Optical modeling and design of Fabry–Perot interferometer sensors for detection of human skin cancer cells","authors":"Milan S. Kovačević , Vladimir Marković , Daniele Tosi , Wilfried Blanc , Ivona Kovačević , Ljubica Kuzmanović","doi":"10.1016/j.ijleo.2025.172622","DOIUrl":"10.1016/j.ijleo.2025.172622","url":null,"abstract":"<div><div>This study presents a method for detecting cancer cells in human skin using a fiber-based sensor, referred to as a semi-distributed Fabry–Pérot interferometer (SDI FP sensor). The sensor employs a multimirror Fabry–Pérot structure formed between a single-mode cleaved fiber tip and a high-scattering fiber, whose core is doped with magnesium silicate nanoparticles, placed in contact with the three principal skin layers: epidermis, dermis, and hypodermis. For the first time, human skin is represented as a four-mirror Fabry–Pérot interferometer, with epidermal refractive index and thickness varying in the presence of cancer cells. First, the reflected spectrum of healthy skin tissue is modeled in the infrared wavelength range. Next, alterations in the reflected spectrum are analyzed in the presence of cancer cells, considering their distribution within each skin layer individually. The results reveal distinct shifts in spectral peaks and valleys between healthy and cancerous tissues, demonstrating the potential of the proposed approach for noninvasive detection of cancer cells across different skin layers. Additionally, a more sophisticated model was considered in which the epidermal refractive index varies randomly due to the presence of cancer cells, reflecting the realistic nonuniform distribution of cancer cells within the epidermal tissue. The proposed model provides a solid theoretical foundation for subsequent experimental validation</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"345 ","pages":"Article 172622"},"PeriodicalIF":3.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145616414","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
Pub Date : 2026-01-01Epub Date: 2025-11-01DOI: 10.1016/j.ijleo.2025.172582
Reda Er-Roukhou , Ossama El Abouti , El Houssaine El Boudouti
In this paper, we proposed a plasmonic sensor based on a waveguide coupled to a triangular ring-like cavity and groove. This structure achieves an ultra-high sensitivity of 1750 nm/RIU and a figure of merit (FOM) of 40. The detection of refractive index changes has been numerically investigated. Simulation results demonstrate that sharp Fano resonance profiles arise from the interference between the discrete modes of the triangular cavity and the continuum modes of the groove-waveguide system. The proposed design exhibits strong potential for applications in high-sensitivity optical biosensing, such as detecting biomolecular interactions, and wavelength-selective optical filtering, leveraging its tunable dual-Fano resonance behavior.
{"title":"Plasmonic sensor based on multiple Fano resonances in metal–insulator–metal waveguide coupled with a triangular ring-like cavity and groove","authors":"Reda Er-Roukhou , Ossama El Abouti , El Houssaine El Boudouti","doi":"10.1016/j.ijleo.2025.172582","DOIUrl":"10.1016/j.ijleo.2025.172582","url":null,"abstract":"<div><div>In this paper, we proposed a plasmonic sensor based on a waveguide coupled to a triangular ring-like cavity and groove. This structure achieves an ultra-high sensitivity of 1750 nm/RIU and a figure of merit (FOM) of 40. The detection of refractive index changes has been numerically investigated. Simulation results demonstrate that sharp Fano resonance profiles arise from the interference between the discrete modes of the triangular cavity and the continuum modes of the groove-waveguide system. The proposed design exhibits strong potential for applications in high-sensitivity optical biosensing, such as detecting biomolecular interactions, and wavelength-selective optical filtering, leveraging its tunable dual-Fano resonance behavior.</div></div>","PeriodicalId":19513,"journal":{"name":"Optik","volume":"344 ","pages":"Article 172582"},"PeriodicalIF":3.1,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145428596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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}
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