Results in Optics最新文献_第2页

Design and optimization of a high-efficiency uniform Si3N4 grating coupler using parameter sweeping and comprehensive performance analysis 基于参数扫描和综合性能分析的高效均匀Si3N4光栅耦合器的设计与优化

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-12 DOI: 10.1016/j.rio.2026.100965

Joyprokash Chakrabartty, Tasreek Ahmed, Biprangshu Paul Joy

Silicon (Si) grating couplers are widely used in photonic applications; however, they suffer from limitations such as high propagation losses and limited bandwidth. In contrast, silicon nitride (Si₃N₄) has attracted increasing interest due to its low optical losses, broader bandwidth, and compatibility with CMOS fabrication processes. These advantages make Si₃N₄ an attractive platform for developing compact, high-performance photonic integrated circuits, particularly for applications in telecommunications, sensing, and other advanced technologies. In this manuscript, we propose a novel grating coupler device architecture entirely based on Si₃N₄ materials. The design features a uniform grating, which simplifies fabrication by eliminating the need for apodization, and incorporates a bottom reflector to enhance coupling efficiency by reducing downward optical losses. A two-dimensional model of the coupler was developed, and detailed finite-difference time-domain (FDTD) simulations were conducted. Through parametric sweeps, optimal values were determined for key parameters including grating period, etch depth, cladding thickness, incident angle, Si₃N₄ thickness, buried oxide layer thickness, source position, and fill factor. The optimized design achieved a coupling efficiency of 76.41 % (−1.1685 dB) at a wavelength of 1550 nm, with a 1 dB bandwidth of 60.31 nm and a 3 dB bandwidth of 95.83 nm. A comparative analysis between efficiencies provided by metal and perfect reflectors was also performed to assess real-world loss factors. The proposed structure exhibits a high tolerance to fabrication, maintaining consistent performance despite variations in its structural parameters. The proposed uniform grating design offers performances comparable to more complex alternatives while being easier to fabricate, making it a practical and efficient solution for Si₃N₄-based grating couplers in modern photonic applications.

硅（Si）光栅耦合器广泛应用于光子领域；然而，它们受到诸如高传播损耗和有限带宽等限制。相比之下，氮化硅（Si3N4）由于其低光学损耗，更宽的带宽以及与CMOS制造工艺的兼容性而吸引了越来越多的兴趣。这些优势使Si3N4成为开发紧凑，高性能光子集成电路的有吸引力的平台，特别是在电信，传感和其他先进技术中的应用。在本文中，我们提出了一种完全基于Si3N4材料的新型光栅耦合器器件结构。该设计的特点是均匀光栅，通过消除apodiization简化了制造，并结合了底部反射器，通过减少向下的光学损耗来提高耦合效率。建立了耦合器的二维模型，并进行了详细的时域有限差分（FDTD）仿真。通过参数扫描，确定光栅周期、蚀刻深度、包层厚度、入射角、氮化硅厚度、埋地氧化层厚度、源位置和填充因子等关键参数的最优值。优化后的设计在1550 nm波长处实现了76.41% （- 1.1685 dB）的耦合效率，1 dB带宽为60.31 nm， 3 dB带宽为95.83 nm。此外，还对金属反射器和完美反射器提供的效率进行了比较分析，以评估实际损耗因素。所提出的结构具有很高的制造耐受性，尽管其结构参数发生变化，但仍能保持一致的性能。所提出的均匀光栅设计提供了与更复杂的替代方案相当的性能，同时更容易制造，使其成为现代光子应用中基于si3n4的光栅耦合器的实用高效的解决方案。

{"title":"Design and optimization of a high-efficiency uniform Si3N4 grating coupler using parameter sweeping and comprehensive performance analysis","authors":"Joyprokash Chakrabartty, Tasreek Ahmed, Biprangshu Paul Joy","doi":"10.1016/j.rio.2026.100965","DOIUrl":"10.1016/j.rio.2026.100965","url":null,"abstract":"<div><div>Silicon (Si) grating couplers are widely used in photonic applications; however, they suffer from limitations such as high propagation losses and limited bandwidth. In contrast, silicon nitride (Si<sub>3</sub>N<sub>4</sub>) has attracted increasing interest due to its low optical losses, broader bandwidth, and compatibility with CMOS fabrication processes. These advantages make Si<sub>3</sub>N<sub>4</sub> an attractive platform for developing compact, high-performance photonic integrated circuits, particularly for applications in telecommunications, sensing, and other advanced technologies. In this manuscript, we propose a novel grating coupler device architecture entirely based on Si<sub>3</sub>N<sub>4</sub> materials. The design features a uniform grating, which simplifies fabrication by eliminating the need for apodization, and incorporates a bottom reflector to enhance coupling efficiency by reducing downward optical losses. A two-dimensional model of the coupler was developed, and detailed finite-difference time-domain (FDTD) simulations were conducted. Through parametric sweeps, optimal values were determined for key parameters including grating period, etch depth, cladding thickness, incident angle, Si<sub>3</sub>N<sub>4</sub> thickness, buried oxide layer thickness, source position, and fill factor. The optimized design achieved a coupling efficiency of 76.41 % (−1.1685 dB) at a wavelength of 1550 nm, with a 1 dB bandwidth of 60.31 nm and a 3 dB bandwidth of 95.83 nm. A comparative analysis between efficiencies provided by metal and perfect reflectors was also performed to assess real-world loss factors. The proposed structure exhibits a high tolerance to fabrication, maintaining consistent performance despite variations in its structural parameters. The proposed uniform grating design offers performances comparable to more complex alternatives while being easier to fabricate, making it a practical and efficient solution for Si<sub>3</sub>N<sub>4</sub>-based grating couplers in modern photonic applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100965"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979971","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}

引用次数: 0

Privacy-preserving image captioning using virtual photon-limited imaging and federated learning 使用虚拟光子限制成像和联合学习保护隐私的图像字幕

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-12 DOI: 10.1016/j.rio.2026.100970

Antoinette Deborah Martin , Inkyu Moon

The growing demand for visual privacy in optical imaging systems has motivated the development of frameworks that can both preserve privacy and maintain utility in downstream tasks. In this work, we propose a privacy-preserving image captioning framework that integrates Poisson Multinomial Distribution-based Photon Counting Imaging (PMD-PCI) with deep learning techniques. PMD-PCI simulates photon-limited imaging conditions by generating highly sparse multispectral images, thereby inherently concealing fine visual details. These sparse representations are used as inputs to two encoder-decoder architectures, ResNet101-Transformer and ViT-Transformer, for automated caption generation. To further enhance privacy and reduce the risk of centralized data exposure, we employ federated learning, allowing model training across distributed clients without direct access to raw images. Experimental evaluations on the Flickr8k and Flickr30k datasets show that accurate captions can be generated from photon-limited images with more than 50,000 incident photons at a resolution of 224 × 224 pixels. On Flickr30k, the proposed ResNet101-Transformer achieves a BLEU-4 score of 17.32 and a CIDEr score of 27.80 at 50,000 photons in a centralized setting, demonstrating that meaningful captions can be produced even under severe optical sparsification. Compared to traditional encryption-based techniques such as Double Random Phase Encoding (DRPE) and AES, our approach provides a better trade-off between privacy and captioning performance. Furthermore, convergence analysis reveals that federated learning achieves near-optimal performance within just 3 communication rounds, significantly reducing the communication overhead required for training. The proposed framework bridges physical-layer image privacy with optical imaging and learning-based caption generation, making it suitable for secure, low-light, or resource-constrained vision systems.

光学成像系统对视觉隐私的需求日益增长，这促使了框架的发展，既可以保护隐私，又可以在下游任务中保持效用。在这项工作中，我们提出了一个保护隐私的图像标题框架，该框架将基于泊松多项式分布的光子计数成像（PMD-PCI）与深度学习技术相结合。PMD-PCI通过生成高度稀疏的多光谱图像来模拟光子受限的成像条件，从而固有地隐藏了精细的视觉细节。这些稀疏表示被用作两个编码器-解码器架构ResNet101-Transformer和viti - transformer的输入，用于自动生成字幕。为了进一步增强隐私并降低集中数据暴露的风险，我们采用了联邦学习，允许跨分布式客户端进行模型训练，而无需直接访问原始图像。在Flickr8k和Flickr30k数据集上的实验评估表明，在分辨率为224 × 224像素的情况下，可以从入射光子超过5万个的光子限制图像中生成准确的标题。在Flickr30k上，提出的ResNet101-Transformer在集中设置的50,000光子下实现了17.32的BLEU-4分数和27.80的CIDEr分数，这表明即使在严重的光学稀疏化下也可以产生有意义的字幕。与传统的基于加密的技术（如双随机相位编码（DRPE）和AES）相比，我们的方法在隐私和字幕性能之间提供了更好的权衡。此外，收敛分析表明，联邦学习仅在3轮通信中就实现了近乎最佳的性能，显著降低了训练所需的通信开销。所提出的框架将物理层图像隐私与光学成像和基于学习的标题生成连接起来，使其适用于安全、低光或资源受限的视觉系统。

{"title":"Privacy-preserving image captioning using virtual photon-limited imaging and federated learning","authors":"Antoinette Deborah Martin , Inkyu Moon","doi":"10.1016/j.rio.2026.100970","DOIUrl":"10.1016/j.rio.2026.100970","url":null,"abstract":"<div><div>The growing demand for visual privacy in optical imaging systems has motivated the development of frameworks that can both preserve privacy and maintain utility in downstream tasks. In this work, we propose a privacy-preserving image captioning framework that integrates Poisson Multinomial Distribution-based Photon Counting Imaging (PMD-PCI) with deep learning techniques. PMD-PCI simulates photon-limited imaging conditions by generating highly sparse multispectral images, thereby inherently concealing fine visual details. These sparse representations are used as inputs to two encoder-decoder architectures, ResNet101-Transformer and ViT-Transformer, for automated caption generation. To further enhance privacy and reduce the risk of centralized data exposure, we employ federated learning, allowing model training across distributed clients without direct access to raw images. Experimental evaluations on the Flickr8k and Flickr30k datasets show that accurate captions can be generated from photon-limited images with more than 50,000 incident photons at a resolution of 224 × 224 pixels. On Flickr30k, the proposed ResNet101-Transformer achieves a BLEU-4 score of 17.32 and a CIDEr score of 27.80 at 50,000 photons in a centralized setting, demonstrating that meaningful captions can be produced even under severe optical sparsification. Compared to traditional encryption-based techniques such as Double Random Phase Encoding (DRPE) and AES, our approach provides a better trade-off between privacy and captioning performance. Furthermore, convergence analysis reveals that federated learning achieves near-optimal performance within just 3 communication rounds, significantly reducing the communication overhead required for training. The proposed framework bridges physical-layer image privacy with optical imaging and learning-based caption generation, making it suitable for secure, low-light, or resource-constrained vision systems.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100970"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979864","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}

引用次数: 0

Dynamic transmission control based on all-dielectric toroidal dipole metasurfaces 基于全介质环形偶极子超表面的动态传输控制

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-12 DOI: 10.1016/j.rio.2026.100966

Ouya Zhang, Shiqi Huang, Yan Li

All-dielectric metasurfaces that support resonators with multiple dipole resonances offer a versatile and effective approach for controlling electromagnetic fields at the nanoscale. Toroidal dipoles, as a peculiar component of multipole resonances, have attracted significant attention due to their unique ability to facilitate light–matter interactions, enabling enhanced absorption, amplified nonlinear responses, advanced data processing and storage capabilities, and highly sensitive sensing applications. The active control of toroidal dipoles in all-dielectric metasurfaces holds great significance for the development of adaptable photonic devices. However, achieving tunable toroidal dipoles in all-dielectric metasurfaces remains challenging due to the volumetric mode property of toroidal dipoles. To address this challenge, we propose a solution by integrating a thin layer of indium tin oxide (ITO) into the all-dielectric metasurfaces. Active modulation of the transmittance amplitude in toroidal dipole-based all-dielectric metasurfaces is achieved by precisely tuning the coupling between the metasurface modes and the ITO thin film. Furthermore, a tunable diffractive grating has been developed based on these findings, demonstrating its prospects for beam direction control applications.

支持具有多个偶极子共振的谐振器的全介电超表面为在纳米尺度上控制电磁场提供了一种通用而有效的方法。环形偶极子，作为多极共振的一个特殊组成部分，由于其独特的促进光-物质相互作用的能力，增强吸收，放大非线性响应，先进的数据处理和存储能力，以及高灵敏度的传感应用，引起了极大的关注。全介电超表面环向偶极子的主动控制对自适应光子器件的研制具有重要意义。然而，由于环面偶极子的体积模式特性，在全介质超表面上实现可调谐环面偶极子仍然具有挑战性。为了应对这一挑战，我们提出了一种解决方案，即将一层薄薄的氧化铟锡（ITO）集成到全介电超表面中。通过精确调节超表面模式与ITO薄膜之间的耦合，实现了环形偶极子基全介电超表面透射率振幅的主动调制。在此基础上，研制了一种可调谐衍射光栅，显示了其在光束方向控制方面的应用前景。

{"title":"Dynamic transmission control based on all-dielectric toroidal dipole metasurfaces","authors":"Ouya Zhang, Shiqi Huang, Yan Li","doi":"10.1016/j.rio.2026.100966","DOIUrl":"10.1016/j.rio.2026.100966","url":null,"abstract":"<div><div>All-dielectric metasurfaces that support resonators with multiple dipole resonances offer a versatile and effective approach for controlling electromagnetic fields at the nanoscale. Toroidal dipoles, as a peculiar component of multipole resonances, have attracted significant attention due to their unique ability to facilitate light–matter interactions, enabling enhanced absorption, amplified nonlinear responses, advanced data processing and storage capabilities, and highly sensitive sensing applications. The active control of toroidal dipoles in all-dielectric metasurfaces holds great significance for the development of adaptable photonic devices. However, achieving tunable toroidal dipoles in all-dielectric metasurfaces remains challenging due to the volumetric mode property of toroidal dipoles. To address this challenge, we propose a solution by integrating a thin layer of indium tin oxide (ITO) into the all-dielectric metasurfaces. Active modulation of the transmittance amplitude in toroidal dipole-based all-dielectric metasurfaces is achieved by precisely tuning the coupling between the metasurface modes and the ITO thin film. Furthermore, a tunable diffractive grating has been developed based on these findings, demonstrating its prospects for beam direction control applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100966"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979972","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}

引用次数: 0

Tuning ZnO thin films via aluminum doping synthesized by co-sputtering: structure, optics, and photoconductivity 共溅射法制备铝掺杂ZnO薄膜：结构、光学和光电导率

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-12 DOI: 10.1016/j.rio.2026.100973

M. Mehrabani , M.M. Shahidi , M.H. Ehsani , F. Shokrian

Aluminum-doped zinc oxide (AZO) thin films are promising for optoelectronic applications, such as transparent electrodes and photodetectors, due to their excellent optical and electrical properties. In this study, AZO thin films were synthesized on glass substrates via co-sputtering using separate ZnO and Al targets. By varying the DC power applied to the Al target (10–25 W), the aluminum doping concentration was controlled, producing samples labeled AZO-10, AZO-15, AZO-20, and AZO-25. The structural, optical, electrical, and photoconductive properties were characterized using XRD, EDX, UV–vis spectroscopy, Hall effect measurements, and I–T (current–time) analysis. XRD revealed an amorphous structure due to low deposition temperatures. EDX confirmed an increase in aluminum content from 0.30% to 1.82% with higher sputtering power. Optical properties exhibited reduced transmittance and a widened bandgap (3.38 eV –3.55 eV), attributed to the Burstein-Moss effect and lattice strain. Electrical properties showed enhanced conductivity, with sheet resistance decreasing from 1.43 × 10⁶ to 1.21 × 10⁴ Ω/□ and carrier concentration increasing from 1.30 × 10¹³ to 5.35 × 10¹⁴ cm⁻², though carrier mobility was limited by the amorphous structure. Photoconductivity measurements under periodic LED illumination demonstrated stable, repeatable photoresponse, with photocurrent decreasing from 120 mA in AZO-10 to 20 mA and 8 mA in AZO-20 and AZO-25, respectively, due to defect states acting as traps and recombination centers induced by higher doping. This study highlights the critical role of optimizing aluminum doping to balance optical transparency, electrical conductivity, and photoconductive performance, establishing co-sputtering as an effective method for tailoring AZO thin films for optoelectronic applications.

铝掺杂氧化锌（AZO）薄膜由于其优异的光学和电学性能，在光电应用领域具有广阔的前景，如透明电极和光电探测器。在本研究中，采用不同的ZnO和Al靶材，通过共溅射在玻璃衬底上合成了AZO薄膜。通过改变施加在Al靶上的直流功率（10-25 W），控制铝掺杂浓度，制备出标记为AZO-10、AZO-15、AZO-20和AZO-25的样品。利用XRD， EDX， UV-vis光谱，霍尔效应测量和I-T（电流-时间）分析表征了结构，光学，电学和光导性能。XRD分析表明，低温沉积形成了非晶结构。EDX证实，铝含量从0.30%增加到1.82%，溅射功率更高。由于Burstein-Moss效应和晶格应变，其透射率降低，带隙变宽（3.38 eV -3.55 eV）。电导率增强，片电阻从1.43 × 106降低到1.21 × 104 Ω/□，载流子浓度从1.30 × 1013增加到5.35 × 1014 cm−2，但载流子迁移率受到非晶结构的限制。在周期性LED照明下的光电导率测量显示出稳定、可重复的光响应，由于高掺杂诱导的缺陷态作为陷阱和复合中心，在AZO-10和AZO-20中，光电流分别从120 mA和8 mA下降到20 mA和8 mA。本研究强调了优化铝掺杂在平衡光学透明度、导电性和光导性能方面的关键作用，并建立了共溅射作为一种有效的方法来定制用于光电应用的AZO薄膜。

{"title":"Tuning ZnO thin films via aluminum doping synthesized by co-sputtering: structure, optics, and photoconductivity","authors":"M. Mehrabani , M.M. Shahidi , M.H. Ehsani , F. Shokrian","doi":"10.1016/j.rio.2026.100973","DOIUrl":"10.1016/j.rio.2026.100973","url":null,"abstract":"<div><div>Aluminum-doped zinc oxide (AZO) thin films are promising for optoelectronic applications, such as transparent electrodes and photodetectors, due to their excellent optical and electrical properties. In this study, AZO thin films were synthesized on glass substrates via co-sputtering using separate ZnO and Al targets. By varying the DC power applied to the Al target (10–25 W), the aluminum doping concentration was controlled, producing samples labeled AZO-10, AZO-15, AZO-20, and AZO-25. The structural, optical, electrical, and photoconductive properties were characterized using XRD, EDX, UV–vis spectroscopy, Hall effect measurements, and I–T (current–time) analysis. XRD revealed an amorphous structure due to low deposition temperatures. EDX confirmed an increase in aluminum content from 0.30% to 1.82% with higher sputtering power. Optical properties exhibited reduced transmittance and a widened bandgap (3.38 eV –3.55 eV), attributed to the Burstein-Moss effect and lattice strain. Electrical properties showed enhanced conductivity, with sheet resistance decreasing from 1.43 × 10<sup>6</sup> to 1.21 × 10<sup>4</sup> Ω/□ and carrier concentration increasing from 1.30 × 10<sup>13</sup> to 5.35 × 10<sup>14</sup> cm<sup>−2</sup>, though carrier mobility was limited by the amorphous structure. Photoconductivity measurements under periodic LED illumination demonstrated stable, repeatable photoresponse, with photocurrent decreasing from 120 mA in AZO-10 to 20 mA and 8 mA in AZO-20 and AZO-25, respectively, due to defect states acting as traps and recombination centers induced by higher doping. This study highlights the critical role of optimizing aluminum doping to balance optical transparency, electrical conductivity, and photoconductive performance, establishing co-sputtering as an effective method for tailoring AZO thin films for optoelectronic applications.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100973"},"PeriodicalIF":3.0,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023851","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}

引用次数: 0

A low-profile wideband antenna loaded with CLS structures for sub-terahertz applications of 6G 为6G次太赫兹应用而装载CLS结构的低轮廓宽带天线

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-07 DOI: 10.1016/j.rio.2026.100960

Md. Mushfiqur Rahman , Md. Shabiul Islam , Wong Hin Yong , Touhidul Alam , Md. Moniruzzaman , Md. Mhedi Hasan , Mohammad Tariqul Islam

In this paper, an arrow-shaped CLS (capacitively loaded strips) structure with a truncated head is inserted between two trapezoid-shaped CLS structures to get a wideband response in the low-frequency region. When the CLS structure without the arrow-shaped structure is excited, a low-frequency resonance is obtained with a 35 GHz bandwidth only. But when the combination is excited by an appropriate feeding network, a low-frequency resonance with a very large bandwidth of about 223 GHz is achieved in the sub-terahertz region of 6G. This combination also causes an unwanted spike-like resonance at low frequency. A T-shaped structure is added to the truncated arrowhead to notch this unnecessary spike. In addition, this structure shifts the lower cutoff frequency by 6 GHz. Simulation results show that the proposed antenna shows a fractional operating bandwidth of 87.24 % from 148 GHz to 377 GHz for |S11| <-10 dB, where a peak realized gain of 4.54 dBi is observed. The antenna also achieves a good bandwidth to dimension ratio of about 995.71. The overall dimension of the antenna is 600 µm × 600 µm × 10 µm, where the height is only 0.005λ, where λ is the operating wavelength at the lower cut-off frequency.

本文在两个梯形CLS结构之间插入一个截头的箭头型CLS结构，以获得低频区域的宽带响应。当不带箭头结构的CLS结构被激发时，得到一个带宽仅为35 GHz的低频共振。但当组合被适当的馈电网络激发时，在6G的次太赫兹区域实现了带宽约为223 GHz的非常大的低频共振。这种组合也会在低频时产生不必要的尖峰状共振。在截断的箭头上添加了一个t形结构来截断这个不必要的尖峰。此外，该结构将较低的截止频率移动了6 GHz。仿真结果表明，该天线在148ghz ~ 377ghz范围内的工作带宽为87.24%，在| - 10db范围内的峰值实现增益为4.54 dBi。该天线还获得了良好的带宽尺寸比，约为995.71。天线的外形尺寸为600µm × 600µm × 10µm，其中高度仅为0.005λ，其中λ为截止频率下的工作波长。

{"title":"A low-profile wideband antenna loaded with CLS structures for sub-terahertz applications of 6G","authors":"Md. Mushfiqur Rahman , Md. Shabiul Islam , Wong Hin Yong , Touhidul Alam , Md. Moniruzzaman , Md. Mhedi Hasan , Mohammad Tariqul Islam","doi":"10.1016/j.rio.2026.100960","DOIUrl":"10.1016/j.rio.2026.100960","url":null,"abstract":"<div><div>In this paper, an arrow-shaped CLS (capacitively loaded strips) structure with a truncated head is inserted between two trapezoid-shaped CLS structures to get a wideband response in the low-frequency region. When the CLS structure without the arrow-shaped structure is excited, a low-frequency resonance is obtained with a 35 GHz bandwidth only. But when the combination is excited by an appropriate feeding network, a low-frequency resonance with a very large bandwidth of about 223 GHz is achieved in the sub-terahertz region of 6G. This combination also causes an unwanted spike-like resonance at low frequency. A T-shaped structure is added to the truncated arrowhead to notch this unnecessary spike. In addition, this structure shifts the lower cutoff frequency by 6 GHz. Simulation results show that the proposed antenna shows a fractional operating bandwidth of 87.24 % from 148 GHz to 377 GHz for |S11| <-10 dB, where a peak realized gain of 4.54 dBi is observed. The antenna also achieves a good bandwidth to dimension ratio of about 995.71. The overall dimension of the antenna is 600 µm × 600 µm × 10 µm, where the height is only 0.005λ, where λ is the operating wavelength at the lower cut-off frequency.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100960"},"PeriodicalIF":3.0,"publicationDate":"2026-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145979863","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}

引用次数: 0

Two-wavelength, dual regime Q-switched erbium-doped fiber laser based on a microfiber loop coated with gold nanostars as the saturable absorber 基于包覆金纳米星作为可饱和吸收剂的超光纤环的双波长双能级调q掺铒光纤激光器

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-06 DOI: 10.1016/j.rio.2026.100957

A. Martinez-Rios , G. Anzueto-Sanchez , J.L. Pichardo-Molina , L.F. Enriquez-Gomez , R.E. Nuñez-Gomez , L.A. Rodriguez-Morales , O. Pottiez , A. Kir’yanov

We report a two-wavelength, dual-regime Q-switched erbium-doped fiber laser employing a microfiber loop coated with gold nanostars as the saturable absorber. The gold nanostars are designed to have three resonances, with the broad spectral tail of the longest resonance overlapping the erbium emission band, enabling strong saturable absorption in the coated microfiber loop, resulting in a modulation depth of 12.19 % and a nonsaturable absorption of 39.89 %. When inserted into an erbium-doped fiber laser ring, this device produced dual Q-switched regimes separated by a continuous-wave window, along with stable dual-wavelength emission at 1529 nm and 1531 nm. In the pump range of 55.7–188 mW, stable Q-switched pulses with repetition rates ranging from 15.8 to 53.36 kHz and pulse widths as short as 5.2 µs were observed. At pump powers of ∼ 190–210 mW, the laser switched to continuous-wave operation; at higher pump levels (211–257 mW), it returned to a Q-switched regime with shorter pulses. This behavior is attributed to the interplay between saturable bleaching and reverse saturable absorption or thermally induced losses in the gold nanostars. These results highlight the potential of multi-resonant plasmonic nanostructures for broadband, intensity-dependent control of fiber lasers.

我们报道了一种双波长、双能级调q掺铒光纤激光器，该激光器采用包覆金纳米星的微光纤环路作为可饱和吸收体。设计的金纳米恒星具有三个共振，其中最长共振的宽频尾与铒发射带重叠，在涂层的微光纤环路中具有强的可饱和吸收，调制深度为12.19%，非饱和吸收为39.89%。当插入掺铒光纤激光环时，该装置产生了由连续波窗口分隔的双q开关状态，以及在1529 nm和1531 nm稳定的双波长发射。在55.7 ~ 188 mW的泵浦范围内，可以观察到重复频率为15.8 ~ 53.36 kHz、脉冲宽度短至5.2µs的稳定调q脉冲。在泵浦功率为~ 190 ~ 210 mW时，激光器切换为连续波工作；在更高的泵浦电平（211-257 mW）下，它以更短的脉冲返回到q开关状态。这种行为归因于饱和漂白和反饱和吸收或热致损失之间的相互作用。这些结果突出了多共振等离子体纳米结构在光纤激光器的宽带、强度依赖控制方面的潜力。

{"title":"Two-wavelength, dual regime Q-switched erbium-doped fiber laser based on a microfiber loop coated with gold nanostars as the saturable absorber","authors":"A. Martinez-Rios , G. Anzueto-Sanchez , J.L. Pichardo-Molina , L.F. Enriquez-Gomez , R.E. Nuñez-Gomez , L.A. Rodriguez-Morales , O. Pottiez , A. Kir’yanov","doi":"10.1016/j.rio.2026.100957","DOIUrl":"10.1016/j.rio.2026.100957","url":null,"abstract":"<div><div>We report a two-wavelength, dual-regime Q-switched erbium-doped fiber laser employing a microfiber loop coated with gold nanostars as the saturable absorber. The gold nanostars are designed to have three resonances, with the broad spectral tail of the longest resonance overlapping the erbium emission band, enabling strong saturable absorption in the coated microfiber loop, resulting in a modulation depth of 12.19 % and a nonsaturable absorption of 39.89 %. When inserted into an erbium-doped fiber laser ring, this device produced dual Q-switched regimes separated by a continuous-wave window, along with stable dual-wavelength emission at 1529 nm and 1531 nm. In the pump range of 55.7–188 mW, stable Q-switched pulses with repetition rates ranging from 15.8 to 53.36 kHz and pulse widths as short as 5.2 µs were observed. At pump powers of ∼ 190–210 mW, the laser switched to continuous-wave operation; at higher pump levels (211–257 mW), it returned to a Q-switched regime with shorter pulses. This behavior is attributed to the interplay between saturable bleaching and reverse saturable absorption or thermally induced losses in the gold nanostars. These results highlight the potential of multi-resonant plasmonic nanostructures for broadband, intensity-dependent control of fiber lasers.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100957"},"PeriodicalIF":3.0,"publicationDate":"2026-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023849","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}

引用次数: 0

Carbon quantum dots synthesized by monochromatic light driven method toward controlling optical and nonlinear optical properties 单色光驱动法合成碳量子点控制光学和非线性光学性质

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-03 DOI: 10.1016/j.rio.2025.100956

Shaghayegh Khalilzadeh , Ehsan Koushki , Mohammad-Reza Zamani-Meymian

In this study, carbon quantum dots (CQDs) were synthesized using pyrolysis method and monochromatic LED light sources were used to control the chemical reaction during the synthetic time. Four monochromatic LEDs with different wavelengths (violet, blue, green and red) were used in these synthetic routes. CQDs were characterized using different methods such as visible-ultraviolet spectroscopy (UV–Vis), dynamic light scattering (DLS), photoluminescence spectroscopy (PL), Fourier transform infrared (FTIR), and Transmission electron spectroscopy (TEM). According to different optical properties of the synthesized CQDs, third order nonlinear absorption coefficients of CQDs have been measured using the open aperture Z-scan technique. Experiments with close aperture Z-scan setup led only to dense patterns of diffraction rings. There was a perfect correlation between the data of all experiments where indicates the effect of monochromatic light radiation on the synthesis process is mainly on the loading of surface agents of the CQDs. With the increase in the wavelength of the irradiated light, it has been witnessed the decrease of surface agents as surface agents, the decrease of hydrodynamic diameter, increase of absorption in the visible region, increase of luminescence and its red shift, the granularity of the particles in the TEM images and increase of the nonlinear properties of the resulting nanocolloids. The present study can be a new window towards control and engineering in the synthesis of CQDs with the help of only a monochromatic light source.

本研究采用热解法合成碳量子点（CQDs），利用单色LED光源控制合成过程中的化学反应。在这些合成路线中使用了四种不同波长的单色led（紫色、蓝色、绿色和红色）。采用可见-紫外光谱（UV-Vis）、动态光散射（DLS）、光致发光光谱（PL）、傅里叶变换红外光谱（FTIR）和透射电子能谱（TEM）等方法对CQDs进行了表征。根据合成CQDs的不同光学性质，利用开孔z扫描技术测量了CQDs的三阶非线性吸收系数。近孔径z扫描实验只得到密集的衍射环图案。结果表明，单色光辐射对CQDs合成过程的影响主要体现在表面活性剂的负载上。随着辐照光波长的增加，表面活性剂的作用减少，流体动力直径减小，可见光区吸收增加，发光及其红移增加，TEM图像中的颗粒粒度增大，所得到的纳米胶体的非线性性质增加。本研究为单色光源合成CQDs的控制和工程化提供了一个新的窗口。

{"title":"Carbon quantum dots synthesized by monochromatic light driven method toward controlling optical and nonlinear optical properties","authors":"Shaghayegh Khalilzadeh , Ehsan Koushki , Mohammad-Reza Zamani-Meymian","doi":"10.1016/j.rio.2025.100956","DOIUrl":"10.1016/j.rio.2025.100956","url":null,"abstract":"<div><div>In this study, carbon quantum dots (CQDs) were synthesized using pyrolysis method and monochromatic LED light sources were used to control the chemical reaction during the synthetic time. Four monochromatic LEDs with different wavelengths (violet, blue, green and red) were used in these synthetic routes. CQDs were characterized using different methods such as visible-ultraviolet spectroscopy (UV–Vis), dynamic light scattering (DLS), photoluminescence spectroscopy (PL), Fourier transform infrared (FTIR), and Transmission electron spectroscopy (TEM). According to different optical properties of the synthesized CQDs, third order nonlinear absorption coefficients of CQDs have been measured using the open aperture Z-scan technique. Experiments with close aperture Z-scan setup led only to dense patterns of diffraction rings. There was a perfect correlation between the data of all experiments where indicates the effect of monochromatic light radiation on the synthesis process is mainly on the loading of surface agents of the CQDs. With the increase in the wavelength of the irradiated light, it has been witnessed the decrease of surface agents as surface agents, the decrease of hydrodynamic diameter, increase of absorption in the visible region, increase of luminescence and its red shift, the granularity of the particles in the TEM images and increase of the nonlinear properties of the resulting nanocolloids. The present study can be a new window towards control and engineering in the synthesis of CQDs with the help of only a monochromatic light source.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"23 ","pages":"Article 100956"},"PeriodicalIF":3.0,"publicationDate":"2026-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145904051","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}

引用次数: 0

Three-dimensional modeling of the relationship between static tunneling and the optical absorption coefficient in tunnel diodes 隧道二极管中静态隧穿与光吸收系数关系的三维建模

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-01 DOI: 10.1016/j.rio.2025.100950

M. Uktamova, Sh. Mamadaliev

This article investigates the Franz–Keldysh effect and the tunneling processes observed in tunnel diodes. The relationship between the optical absorption coefficient and the tunneling probability is analyzed using both theoretical and graphical methods. The dependence of both processes on energy is illustrated through 3D graphs. The surfaces defined according to the energy level distribution may contribute to improving the efficiency of optoelectronic devices based on tunnel diodes.

本文研究了在隧道二极管中观察到的弗兰兹-凯迪什效应和隧道过程。用理论和图解的方法分析了光吸收系数与隧穿概率的关系。这两个过程对能量的依赖关系通过三维图形来说明。根据能级分布定义的表面有助于提高基于隧道二极管的光电器件的效率。

引用次数: 0

Design and simulation of a high sensitivity 2D photonic crystal waveguide biosensor for vitiligo detection 用于白癜风检测的高灵敏度二维光子晶体波导生物传感器设计与仿真

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-01 DOI: 10.1016/j.rio.2025.100954

Zaineb Gharsallah , V R Balaji , Monia Najjar , Gopalkrishna Hegde , Massoudi Radhouene

In this work, we present a high-performance Optical biosensor for the non-invasive detection of vitiligo, a skin disorder characterized by depigmentation resulting from melanin loss.. The sensor is designed on a two-dimensional (2D) Photonic Crystal (PhC) slab fabricated on a silicon-on-insulator (SOI) platform with a triangular lattice of air holes. The proposed design incorporates an input bus waveguide, a circular ring cavity, a hexagonal centre ring, a triangular ring, and an output drop waveguide to achieve strong resonance coupling and field confinement. The biosensor operates by monitoring refractive index variations of the skin analyte, which correlate with changes in melanin and keratin concentration. Resonant wavelength shifts are used to quantify these variations, enabling accurate identification of vitiligo-related anomalies.This sensor exhibits high-performance specifications, with a maximum quality factor of 16,388 for keratin-related conditions, a minimum spectral line width of 0.1 nm for all conditions, and a maximum sensitivity of 175 nm/RIU for melanin-related conditions. The device has a compact footprint of 97.52 µm² makes it suitable for on-chip biomedical integration. Unlike conventional PhC biosensors that restrict analyte infiltration to limited regions, this device is designed to fill the entire PhC structure with the analyte, rather than confining it to a specific region of the structure, which helps increase the reliability and repeatability of measurements. The sensor offers a promising platform for non-invasive and accurate detection of vitiligo.

在这项工作中，我们提出了一种高性能的光学生物传感器，用于非侵入性检测白癜风，白癜风是一种皮肤疾病，其特征是黑色素丢失导致的色素沉着。该传感器被设计在二维光子晶体（PhC）板上，该板在绝缘体上的硅（SOI）平台上制造，具有三角形的空气孔晶格。该设计包括输入母线波导、环形腔、六角形中心环、三角形环和输出滴波导，以实现强共振耦合和场约束。生物传感器通过监测皮肤分析物的折射率变化来工作，这与黑色素和角蛋白浓度的变化有关。共振波长位移用于量化这些变化，从而准确识别白癜风相关的异常。该传感器具有高性能规格，角蛋白相关条件下的最大质量因子为16,388，所有条件下的最小谱线宽度为0.1 nm，黑色素相关条件下的最大灵敏度为175 nm/RIU。该器件的占地面积为97.52µm2，适用于片上生物医学集成。与传统的PhC生物传感器将分析物浸润限制在有限区域不同，该设备旨在将分析物填充整个PhC结构，而不是将其限制在结构的特定区域，这有助于提高测量的可靠性和可重复性。该传感器为白癜风的无创准确检测提供了一个有前景的平台。

{"title":"Design and simulation of a high sensitivity 2D photonic crystal waveguide biosensor for vitiligo detection","authors":"Zaineb Gharsallah , V R Balaji , Monia Najjar , Gopalkrishna Hegde , Massoudi Radhouene","doi":"10.1016/j.rio.2025.100954","DOIUrl":"10.1016/j.rio.2025.100954","url":null,"abstract":"<div><div>In this work, we present a high-performance Optical biosensor for the non-invasive detection of vitiligo, a skin disorder characterized by depigmentation resulting from melanin loss.. The sensor is designed on a two-dimensional (2D) Photonic Crystal (PhC) slab fabricated on a silicon-on-insulator (SOI) platform with a triangular lattice of air holes. The proposed design incorporates an input bus waveguide, a circular ring cavity, a hexagonal centre ring, a triangular ring, and an output drop waveguide to achieve strong resonance coupling and field confinement. The biosensor operates by monitoring refractive index variations of the skin analyte, which correlate with changes in melanin and keratin concentration. Resonant wavelength shifts are used to quantify these variations, enabling accurate identification of vitiligo-related anomalies.This sensor exhibits high-performance specifications, with a maximum quality factor of 16,388 for keratin-related conditions, a minimum spectral line width of 0.1 nm for all conditions, and a maximum sensitivity of 175 nm/RIU for melanin-related conditions. The device has a compact footprint of 97.52 µm<sup>2</sup> makes it suitable for on-chip biomedical integration. Unlike conventional PhC biosensors that restrict analyte infiltration to limited regions, this device is designed to fill the entire PhC structure with the analyte, rather than confining it to a specific region of the structure, which helps increase the reliability and repeatability of measurements. The sensor offers a promising platform for non-invasive and accurate detection of vitiligo.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"22 ","pages":"Article 100954"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938521","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}

引用次数: 0

Algorithmic optimization of figure-of-9 fiber lasers via particle swarm methods 基于粒子群方法的9形光纤激光器算法优化

IF 3 Q3 Physics and Astronomy

Results in Optics

Pub Date : 2026-01-01 DOI: 10.1016/j.rio.2025.100955

Gaelle Carine Mbanda Nsoungui , Abdullah S. Karar , Kaboko Jean-Jacques Monga , Ehsan Adibnia , Hafedh Mahmoud Zayani , Mohamed Salhi , Faouzi Bahloul , Khmaies Ouahada

Figure-of-9 fiber lasers (F9FL) represent a significant advancement in the field of ultrafast photonics, offering improved environmental stability, enhanced self-starting behavior, and efficient pulse shaping. However, optimizing the performance of F9FL remains a challenging task due to the complex interplay between nonlinear dynamics, dispersion management, and gain saturation effects. This study presents a systematic approach to optimize the operating conditions of an F9FL using an advanced two-particle swarm optimization (PSO) algorithm. The optimization process aims to maximize pulse energy, improve temporal stability, and enhance mode-locking efficiency by tuning critical laser parameters such as fiber lengths, gain coefficients, and phase shift conditions. A comprehensive numerical model incorporating bidirectional pulse propagation and nonlinear effects is employed to evaluate performance metrics under realistic constraints. Simulation results demonstrate that the proposed PSO-based strategy effectively identifies optimal parameter sets that lead to high-energy single pulses with stable temporal profiles. The findings offer practical guidelines for experimental implementation and highlight the potential of evolutionary algorithms for accelerating fiber laser design and optimization in advanced nonlinear optical systems.

图-9光纤激光器（F9FL）代表了超快光子学领域的重大进步，提供了更好的环境稳定性，增强的自启动行为和高效的脉冲整形。然而，由于非线性动力学、色散管理和增益饱和效应之间复杂的相互作用，优化F9FL的性能仍然是一项具有挑战性的任务。本文提出了一种采用先进的双粒子群优化（PSO）算法对F9FL运行条件进行系统优化的方法。优化过程旨在通过调整光纤长度、增益系数和相移条件等关键激光参数来最大化脉冲能量、提高时间稳定性和提高锁模效率。综合考虑双向脉冲传播和非线性效应的数值模型在实际约束条件下对性能指标进行了评价。仿真结果表明，该策略能有效地识别出时间分布稳定的高能单脉冲的最优参数集。这些发现为实验实现提供了实用指南，并突出了进化算法在加速先进非线性光学系统中光纤激光器设计和优化方面的潜力。

{"title":"Algorithmic optimization of figure-of-9 fiber lasers via particle swarm methods","authors":"Gaelle Carine Mbanda Nsoungui , Abdullah S. Karar , Kaboko Jean-Jacques Monga , Ehsan Adibnia , Hafedh Mahmoud Zayani , Mohamed Salhi , Faouzi Bahloul , Khmaies Ouahada","doi":"10.1016/j.rio.2025.100955","DOIUrl":"10.1016/j.rio.2025.100955","url":null,"abstract":"<div><div>Figure-of-9 fiber lasers (F9FL) represent a significant advancement in the field of ultrafast photonics, offering improved environmental stability, enhanced self-starting behavior, and efficient pulse shaping. However, optimizing the performance of F9FL remains a challenging task due to the complex interplay between nonlinear dynamics, dispersion management, and gain saturation effects. This study presents a systematic approach to optimize the operating conditions of an F9FL using an advanced two-particle swarm optimization (PSO) algorithm. The optimization process aims to maximize pulse energy, improve temporal stability, and enhance mode-locking efficiency by tuning critical laser parameters such as fiber lengths, gain coefficients, and phase shift conditions. A comprehensive numerical model incorporating bidirectional pulse propagation and nonlinear effects is employed to evaluate performance metrics under realistic constraints. Simulation results demonstrate that the proposed PSO-based strategy effectively identifies optimal parameter sets that lead to high-energy single pulses with stable temporal profiles. The findings offer practical guidelines for experimental implementation and highlight the potential of evolutionary algorithms for accelerating fiber laser design and optimization in advanced nonlinear optical systems.</div></div>","PeriodicalId":21151,"journal":{"name":"Results in Optics","volume":"22 ","pages":"Article 100955"},"PeriodicalIF":3.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145938523","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}

引用次数: 0