This work presents a novel approach to create and dynamically control quasi-bound states in the continuum (BIC) resonances through the hybridization of 1D and 2D metasurfaces using micro-electromechanical systems (MEMS). The quasi-BIC resonance’s central wavelength and quality factor are precisely tuned by introducing out-of-plane symmetry breaking through a silicon MEMS membrane positioned above a 1D silicon metasurface. The proposed design achieves ultranarrow resonance linewidths with the spectral tuning range exceeding 60 nm while maintaining a constant quality factor. This tuning capability, realized through both horizontal displacement within a 1D metasurface and vertical MEMS membrane movement, offers a new degree of freedom for manipulating quasi-BIC resonances. The proposed hybridization of 2D and 1D metasurfaces using a MEMS mechanism provides a practical route to dynamic modulation of transmission resonance characteristics, making it a promising candidate for tunable filters, spectroscopy, imaging, and sensing applications.
{"title":"Tunable bound states in the continuum through hybridization of 1D and 2D metasurfaces","authors":"Fedor Kovalev, Mariusz Martyniuk, Andrey Miroshnichenko, Ilya Shadrivov","doi":"10.1515/nanoph-2025-0432","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0432","url":null,"abstract":"This work presents a novel approach to create and dynamically control quasi-bound states in the continuum (BIC) resonances through the hybridization of 1D and 2D metasurfaces using micro-electromechanical systems (MEMS). The quasi-BIC resonance’s central wavelength and quality factor are precisely tuned by introducing out-of-plane symmetry breaking through a silicon MEMS membrane positioned above a 1D silicon metasurface. The proposed design achieves ultranarrow resonance linewidths with the spectral tuning range exceeding 60 nm while maintaining a constant quality factor. This tuning capability, realized through both horizontal displacement within a 1D metasurface and vertical MEMS membrane movement, offers a new degree of freedom for manipulating quasi-BIC resonances. The proposed hybridization of 2D and 1D metasurfaces using a MEMS mechanism provides a practical route to dynamic modulation of transmission resonance characteristics, making it a promising candidate for tunable filters, spectroscopy, imaging, and sensing applications.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"80 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145484726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-10DOI: 10.1515/nanoph-2025-0398
Qilin Zheng, Li Liang, Shunji Yang, Luyang Tong, Wenqiang Wang, Jibo Tang, Yu Zhang, Bintong Huang, Xiaobo He
Spectroscopy underpins a wide range of applications, including biomedical diagnostics, precision agriculture, remote sensing, and industrial process control. Recent advances in silicon and microwave photonic integration have facilitated the miniaturization of spectroscopic systems, enabling portable, real-time analysis. However, the realization of a chip-scale platform that simultaneously achieves broadband coverage, high resolution, and scalable low-cost fabrication – particularly in the near-infrared (NIR) regime – remains a significant challenge. Here, we present a compact and cost-effective NIR spectroscopic sensing chip that monolithically integrates a plasmonic bandpass filter array with InGaAs photodetectors. The device is fabricated via single-step lithography and features a nanohole array with geometrically tunable narrowband transmission spanning 900–1,700 nm, exhibiting a full width at half maximum (FWHM) of 5.0 nm and a peak Q -factor of ∼284. The plasmonic filters are directly integrated with the detectors through a SiN x spacer layer, eliminating post-fabrication alignment and enhancing scalability. A 16-channel super-pixel layout, combined with computational spectral reconstruction, enables ∼1 nm resolution near 1,550 nm and supports high-fidelity spectral imaging. This work demonstrates a scalable, detector-compatible approach to on-chip NIR spectroscopy, offering a promising route toward deployable, compact spectral sensing platforms.
{"title":"Broadband on-chip spectral sensing via directly integrated narrowband plasmonic filters for computational multispectral imaging","authors":"Qilin Zheng, Li Liang, Shunji Yang, Luyang Tong, Wenqiang Wang, Jibo Tang, Yu Zhang, Bintong Huang, Xiaobo He","doi":"10.1515/nanoph-2025-0398","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0398","url":null,"abstract":"Spectroscopy underpins a wide range of applications, including biomedical diagnostics, precision agriculture, remote sensing, and industrial process control. Recent advances in silicon and microwave photonic integration have facilitated the miniaturization of spectroscopic systems, enabling portable, real-time analysis. However, the realization of a chip-scale platform that simultaneously achieves broadband coverage, high resolution, and scalable low-cost fabrication – particularly in the near-infrared (NIR) regime – remains a significant challenge. Here, we present a compact and cost-effective NIR spectroscopic sensing chip that monolithically integrates a plasmonic bandpass filter array with InGaAs photodetectors. The device is fabricated via single-step lithography and features a nanohole array with geometrically tunable narrowband transmission spanning 900–1,700 nm, exhibiting a full width at half maximum (FWHM) of 5.0 nm and a peak <jats:italic>Q</jats:italic> -factor of ∼284. The plasmonic filters are directly integrated with the detectors through a SiN <jats:sub> <jats:italic>x</jats:italic> </jats:sub> spacer layer, eliminating post-fabrication alignment and enhancing scalability. A 16-channel super-pixel layout, combined with computational spectral reconstruction, enables ∼1 nm resolution near 1,550 nm and supports high-fidelity spectral imaging. This work demonstrates a scalable, detector-compatible approach to on-chip NIR spectroscopy, offering a promising route toward deployable, compact spectral sensing platforms.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"39 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145484831","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-09DOI: 10.1515/nanoph-2025-0296
Jiawei Zhang, Weipeng Zhang, Tengji Xu, Lei Xu, Eli A. Doris, Bhavin J. Shastri, Chaoran Huang, Paul R. Prucnal
CMOS-compatible photonic integrated circuits (PICs) are emerging as a promising platform in artificial intelligence (AI) computing. Owing to the compact footprint of microring resonators (MRRs) and the enhanced interconnect efficiency enabled by wavelength division multiplexing (WDM), MRR-based photonic neural networks (PNNs) are particularly promising for large-scale integration. However, the scalability and energy efficiency of such systems are fundamentally limited by the MRR resonance wavelength variations induced by fabrication process variations (FPVs) and environmental fluctuations. Existing solutions use post-fabrication approaches or thermo-optic tuning, incurring high control power and additional process complexity. In this work, we introduce an online training and pruning method that addresses this challenge, adapting to FPV-induced and thermally induced shifts in MRR resonance wavelength. By incorporating a power-aware pruning term into the conventional loss function, our approach simultaneously optimizes the PNN accuracy and the total power consumption for MRR tuning. In proof-of-concept on-chip experiments on the Iris dataset, our system PNNs can adaptively train to maintain above 90 % classification accuracy in a wide temperature range of 26–40 °C while achieving a 44.7 % reduction in tuning power via pruning. Additionally, our approach reduces the power consumption by orders-of-magnitude on larger datasets. By addressing chip-to-chip variation and minimizing power requirements, our approach significantly improves the scalability and energy efficiency of MRR-based integrated analog photonic processors, paving the way for large-scale PICs to enable versatile applications including neural networks, photonic switching, LiDAR, and radio-frequency beamforming.
{"title":"Online training and pruning of multi-wavelength photonic neural networks","authors":"Jiawei Zhang, Weipeng Zhang, Tengji Xu, Lei Xu, Eli A. Doris, Bhavin J. Shastri, Chaoran Huang, Paul R. Prucnal","doi":"10.1515/nanoph-2025-0296","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0296","url":null,"abstract":"CMOS-compatible photonic integrated circuits (PICs) are emerging as a promising platform in artificial intelligence (AI) computing. Owing to the compact footprint of microring resonators (MRRs) and the enhanced interconnect efficiency enabled by wavelength division multiplexing (WDM), MRR-based photonic neural networks (PNNs) are particularly promising for large-scale integration. However, the scalability and energy efficiency of such systems are fundamentally limited by the MRR resonance wavelength variations induced by fabrication process variations (FPVs) and environmental fluctuations. Existing solutions use post-fabrication approaches or thermo-optic tuning, incurring high control power and additional process complexity. In this work, we introduce an online training and pruning method that addresses this challenge, adapting to FPV-induced and thermally induced shifts in MRR resonance wavelength. By incorporating a power-aware pruning term into the conventional loss function, our approach simultaneously optimizes the PNN accuracy and the total power consumption for MRR tuning. In proof-of-concept on-chip experiments on the Iris dataset, our system PNNs can adaptively train to maintain above 90 % classification accuracy in a wide temperature range of 26–40 °C while achieving a 44.7 % reduction in tuning power via pruning. Additionally, our approach reduces the power consumption by orders-of-magnitude on larger datasets. By addressing chip-to-chip variation and minimizing power requirements, our approach significantly improves the scalability and energy efficiency of MRR-based integrated analog photonic processors, paving the way for large-scale PICs to enable versatile applications including neural networks, photonic switching, LiDAR, and radio-frequency beamforming.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"133 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145472882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-09DOI: 10.1515/nanoph-2025-0391
Amir Ali Marefati, Mahdieh Bozorgi
We present a high performance ultra-broadband optical absorber based on a metal–insulator–metal (MIM) configuration, enhanced by two-dimensional (2D) materials: graphene and borophene. The base design includes a titanium resonator, an SiO 2 dielectric spacer, and a gold ground plane. Performance optimization is achieved through integration of 2D materials, anti-reflection coatings (ARC), and tuning of structural parameters, Fermi energy, and surface carrier density. Numerical simulations using the finite difference time domain (FDTD) method show that incorporating borophene, due to its exceptionally high carrier density, leads to remarkable enhancement in both absorption amplitude and spectral bandwidth. When integrated with an optimized antireflection coating (ARC), the borophene-based absorber achieves over 90 % absorption across 790–3,232 nm (bandwidth: 2,442 nm), corresponding to a 136 % enhancement over the base design. For absorption above 80 %, the bandwidth extends from 760 to 3,306 nm (2,546 nm), yielding a 125 % improvement. The associated fractional bandwidths are 121 % and 125 %, respectively. By comparison, the graphene-based counterpart, with a properly tuned ARC and Fermi level, delivers over 90 % absorption within 923–2,108 nm (1,185 nm, 13 % improvement), while maintaining absorption above 80 % across 911–2,256 nm (1,345 nm, 12 % improvement), with corresponding fractional bandwidths of 78 % and 84 %. Comparative analysis underscores the critical importance of 2D material selection and placement, ARC and resonator optimization, and optical tuning in achieving optimal performance. These results indicate strong potential for practical applications in advanced optoelectronic and photonic devices, including infrared imaging, optical sensing, broadband photodetectors, solar energy harvesting, and stealth or thermal camouflage systems.
{"title":"Record-level, exceptionally broadband borophene-based absorber with near-perfect absorption: design and comparison with a graphene-based counterpart","authors":"Amir Ali Marefati, Mahdieh Bozorgi","doi":"10.1515/nanoph-2025-0391","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0391","url":null,"abstract":"We present a high performance ultra-broadband optical absorber based on a metal–insulator–metal (MIM) configuration, enhanced by two-dimensional (2D) materials: graphene and borophene. The base design includes a titanium resonator, an SiO <jats:sub>2</jats:sub> dielectric spacer, and a gold ground plane. Performance optimization is achieved through integration of 2D materials, anti-reflection coatings (ARC), and tuning of structural parameters, Fermi energy, and surface carrier density. Numerical simulations using the finite difference time domain (FDTD) method show that incorporating borophene, due to its exceptionally high carrier density, leads to remarkable enhancement in both absorption amplitude and spectral bandwidth. When integrated with an optimized antireflection coating (ARC), the borophene-based absorber achieves over 90 % absorption across 790–3,232 nm (bandwidth: 2,442 nm), corresponding to a 136 % enhancement over the base design. For absorption above 80 %, the bandwidth extends from 760 to 3,306 nm (2,546 nm), yielding a 125 % improvement. The associated fractional bandwidths are 121 % and 125 %, respectively. By comparison, the graphene-based counterpart, with a properly tuned ARC and Fermi level, delivers over 90 % absorption within 923–2,108 nm (1,185 nm, 13 % improvement), while maintaining absorption above 80 % across 911–2,256 nm (1,345 nm, 12 % improvement), with corresponding fractional bandwidths of 78 % and 84 %. Comparative analysis underscores the critical importance of 2D material selection and placement, ARC and resonator optimization, and optical tuning in achieving optimal performance. These results indicate strong potential for practical applications in advanced optoelectronic and photonic devices, including infrared imaging, optical sensing, broadband photodetectors, solar energy harvesting, and stealth or thermal camouflage systems.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"80 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145472744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Dynamically tunable metasurfaces based on phase-change materials (PCMs) have become important platforms for realizing reconfigurable optical systems. Nevertheless, achieving multiple independent functionalities within a single device, particularly under polarization multiplexing, remains difficult due to limited design flexibility. In this study, we present a metasurface design framework that reaches the theoretical maximum of six independent phase modulation functions by simultaneously controlling the polarization states and the crystallinity of the PCM. This is implemented through a pixel-extension strategy, where each nanofin functions independently in amorphous state and is reorganized into superpixels with distinct optical responses in crystalline state. To support this, a forward filtering algorithm is developed to efficiently determine structural configurations under dual-state constraints. The effectiveness of the proposed approach is confirmed through two representative implementations, including dynamically switchable multifocal metalenses and multichannel holography. In addition, a progressive encoding strategy is introduced, which deliberately utilizes inter-state crosstalk to hierarchically embed optical information across material states. This compact and reconfigurable metasurface platform offers high functional density and flexible control, holding strong potential for applications in optical communication, information encryption, and adaptive display technologies.
{"title":"Dual-state six-channel polarization multiplexing in reconfigurable metasurfaces","authors":"Sujun Xie, Tianxu Jia, Xiaoyue Ma, Bingjue Li, Ruohu Zhang, Zhigang Li, Binfeng Yun, Hyeonsu Heo, Nara Jeon, Guanghao Rui, Junsuk Rho","doi":"10.1515/nanoph-2025-0403","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0403","url":null,"abstract":"Dynamically tunable metasurfaces based on phase-change materials (PCMs) have become important platforms for realizing reconfigurable optical systems. Nevertheless, achieving multiple independent functionalities within a single device, particularly under polarization multiplexing, remains difficult due to limited design flexibility. In this study, we present a metasurface design framework that reaches the theoretical maximum of six independent phase modulation functions by simultaneously controlling the polarization states and the crystallinity of the PCM. This is implemented through a pixel-extension strategy, where each nanofin functions independently in amorphous state and is reorganized into superpixels with distinct optical responses in crystalline state. To support this, a forward filtering algorithm is developed to efficiently determine structural configurations under dual-state constraints. The effectiveness of the proposed approach is confirmed through two representative implementations, including dynamically switchable multifocal metalenses and multichannel holography. In addition, a progressive encoding strategy is introduced, which deliberately utilizes inter-state crosstalk to hierarchically embed optical information across material states. This compact and reconfigurable metasurface platform offers high functional density and flexible control, holding strong potential for applications in optical communication, information encryption, and adaptive display technologies.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"51 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145472881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-09DOI: 10.1515/nanoph-2025-0488
Jiantao Ma, Shunfa Liu, Chengjie Lu, Ying Yu, Bo Chen, Jin Liu
Optical skyrmions, as structured light fields endowed with discrete topological numbers, open new opportunities for high-density encoding, robust information transport, and quantum light–matter interactions. However, most existing skyrmion generators rely on complex or bulky systems, hindering their application in scalable on-chip quantum technologies. Here, we propose a nanophotonic scheme based on semiconductor cavity quantum electrodynamics, whereby a circularly polarized quantum emitter is coupled to a concentric bullseye resonator. This configuration enables the efficient generation of single-photon Stokes vector skyrmions at subwavelength scales, as well as their high-order extensions. By exciting single-photon sources at different positions, the skyrmion number can be continuously switched between +2 and −2, while higher-order states are accessible by tuning the radius of cavity’s center disc. This strategy couples the topological dimension of skyrmions with quantum states, laying the groundwork for quantum skyrmions in on-chip topological keying and quantum readout. Our work provides a practical device architecture for integrated nanophotonic quantum topological state platforms, offering a new paradigm for topologically protected quantum communications and on-chip quantum information processing.
{"title":"Bright single-photon skyrmion sources in bullseye cavities","authors":"Jiantao Ma, Shunfa Liu, Chengjie Lu, Ying Yu, Bo Chen, Jin Liu","doi":"10.1515/nanoph-2025-0488","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0488","url":null,"abstract":"Optical skyrmions, as structured light fields endowed with discrete topological numbers, open new opportunities for high-density encoding, robust information transport, and quantum light–matter interactions. However, most existing skyrmion generators rely on complex or bulky systems, hindering their application in scalable on-chip quantum technologies. Here, we propose a nanophotonic scheme based on semiconductor cavity quantum electrodynamics, whereby a circularly polarized quantum emitter is coupled to a concentric bullseye resonator. This configuration enables the efficient generation of single-photon Stokes vector skyrmions at subwavelength scales, as well as their high-order extensions. By exciting single-photon sources at different positions, the skyrmion number can be continuously switched between +2 and −2, while higher-order states are accessible by tuning the radius of cavity’s center disc. This strategy couples the topological dimension of skyrmions with quantum states, laying the groundwork for quantum skyrmions in on-chip topological keying and quantum readout. Our work provides a practical device architecture for integrated nanophotonic quantum topological state platforms, offering a new paradigm for topologically protected quantum communications and on-chip quantum information processing.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"138 6 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145472684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
Polarization control plasmonic nanostructures provide a unique route to manipulate light–matter interactions at the nanoscale and are particularly powerful for information security applications, where polarization-encoded color images can be used for optical encryption and anticounterfeiting. Conventional plasmonic materials such as Au and Ag, however, suffer from poor thermal stability, limiting their integration into robust, CMOS-compatible devices. Here, we present a polarization-encoded color image platform based on refractory HfN plasmonic metasurfaces, which combine gold-like optical properties with exceptional hardness, compositional tunability, and superior high-temperature resilience. Periodically patterned HfN nanoantennas with widths of 200 nm exhibit well-defined localized surface plasmon resonances in the visible spectrum (628 and 564 nm) and can be selectively excited by orthogonal linear polarizations. We designed and realized a polarization-encoded color image in which distinct color channels are revealed under x- and y-polarized illumination, enabling decryption of hidden information. Under unpolarized illumination, the superposition of color channels effectively conceals the message, achieving robust optical encryption. Our results establish HfN plasmonic nanostructures as a key material platform for next-generation nanophotonics, uniquely combining gold-like optical properties with exceptional thermal robustness. Even after high-temperature annealing, HfN retains its plasmonic response, enabling reliable polarization-resolved color image encoding and decryption. This breakthrough paves the way for thermally resilient metasurfaces for secure data encryption, anticounterfeiting, and robust operation in extreme environments.
{"title":"Polarization-encoded color images for information encryption enabled by HfN refractory plasmonic metasurfaces","authors":"Yu-Cheng Chu, Tzu-Yu Peng, Chen-Yu Wang, Shyr-Shyan Yeh, Jia-Wern Chen, Yu-Jung Lu","doi":"10.1515/nanoph-2025-0502","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0502","url":null,"abstract":"Polarization control plasmonic nanostructures provide a unique route to manipulate light–matter interactions at the nanoscale and are particularly powerful for information security applications, where polarization-encoded color images can be used for optical encryption and anticounterfeiting. Conventional plasmonic materials such as Au and Ag, however, suffer from poor thermal stability, limiting their integration into robust, CMOS-compatible devices. Here, we present a polarization-encoded color image platform based on refractory HfN plasmonic metasurfaces, which combine gold-like optical properties with exceptional hardness, compositional tunability, and superior high-temperature resilience. Periodically patterned HfN nanoantennas with widths of 200 nm exhibit well-defined localized surface plasmon resonances in the visible spectrum (628 and 564 nm) and can be selectively excited by orthogonal linear polarizations. We designed and realized a polarization-encoded color image in which distinct color channels are revealed under x- and y-polarized illumination, enabling decryption of hidden information. Under unpolarized illumination, the superposition of color channels effectively conceals the message, achieving robust optical encryption. Our results establish HfN plasmonic nanostructures as a key material platform for next-generation nanophotonics, uniquely combining gold-like optical properties with exceptional thermal robustness. Even after high-temperature annealing, HfN retains its plasmonic response, enabling reliable polarization-resolved color image encoding and decryption. This breakthrough paves the way for thermally resilient metasurfaces for secure data encryption, anticounterfeiting, and robust operation in extreme environments.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"98 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145472745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-07DOI: 10.1515/nanoph-2025-0435
Ulrich Hohenester, Felix Hitzelhammer, Georg Krainer, Peter Banzer, Thomas Juffmann
We employ the concept of quantum Fisher information to optimize the focused excitation fields in coherent scattering microscopy. Our optimization goal is to achieve the best possible localization precision for small scatterers located above a glass coverslip, while keeping the intensity of the total incoming excitation fields fixed. For small numerical aperture (NA) values, the optimal fields have linear or circular polarization, and the excitation beam can be well approximated by a Gaussian one. For larger NA values, the optimal beam acquires radial polarization. We show that the high localization precision can be attributed to high field strengths at the scatterer position, and correspondingly a large number of scattered and detected photons. Finally, we evaluate the performance of the optimized beams in interferometric scattering microscopy (i scat ), and further optimize these fields for i scat localization using the concept of Fisher information.
{"title":"Optimizing the localization precision in coherent scattering microscopy using structured light","authors":"Ulrich Hohenester, Felix Hitzelhammer, Georg Krainer, Peter Banzer, Thomas Juffmann","doi":"10.1515/nanoph-2025-0435","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0435","url":null,"abstract":"We employ the concept of quantum Fisher information to optimize the focused excitation fields in coherent scattering microscopy. Our optimization goal is to achieve the best possible localization precision for small scatterers located above a glass coverslip, while keeping the intensity of the total incoming excitation fields fixed. For small numerical aperture (NA) values, the optimal fields have linear or circular polarization, and the excitation beam can be well approximated by a Gaussian one. For larger NA values, the optimal beam acquires radial polarization. We show that the high localization precision can be attributed to high field strengths at the scatterer position, and correspondingly a large number of scattered and detected photons. Finally, we evaluate the performance of the optimized beams in interferometric scattering microscopy (i <jats:sc>scat</jats:sc> ), and further optimize these fields for i <jats:sc>scat</jats:sc> localization using the concept of Fisher information.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"234 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145454959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-07DOI: 10.1515/nanoph-2025-0430
Xusheng Chen, Fanfei Meng, Kang Du, Min Lin, Luping Du
Light exhibits both spin and orbital angular momentum (SAM and OAM). These two forms of angular momentum remain independent in paraxial fields, but become coupled in confined fields through spin–orbit interactions (SOI). The SOI mechanism allows for the manipulation of SAM to generate structured light fields featuring nontrivial topological characteristics, such as optical skyrmions. Conventional OAM beams, nonetheless, carry discrete integer topological charges (TCs), leading to discrete SAM states. This discrete property poses a persistent challenge for achieving continuous control of SAM. To tackle this fundamental issue, we explored fractional orbital angular momentum (FOAM) beams, whose TCs are extended from integers to fractions, to realize continuous and precise control of SAM. A direct mathematical relationship between the fractional effective TCs of FOAM beams and the orientation distributions of the SAM vector has been derived. This theoretical prediction has been experimentally verified using our home-built near-field mapping system, by which the distinct SAM distributions of surface cosine waves regulated by FOAM beams were mapped out. As a potential application, we also devised an inverse detection method to accurately measure the fractional effective TCs of FOAM, which achieved theoretical and experimental accuracies of 10 −5 and 10 −2 , respectively. These advancements may enhance our fundamental understanding of the SOI mechanism, and hence could create novel opportunities for light field manipulation, optical communication, and other related areas.
{"title":"Spin angular momentum modulation via spin–orbit interaction in fractional orbital angular momentum beams","authors":"Xusheng Chen, Fanfei Meng, Kang Du, Min Lin, Luping Du","doi":"10.1515/nanoph-2025-0430","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0430","url":null,"abstract":"Light exhibits both spin and orbital angular momentum (SAM and OAM). These two forms of angular momentum remain independent in paraxial fields, but become coupled in confined fields through spin–orbit interactions (SOI). The SOI mechanism allows for the manipulation of SAM to generate structured light fields featuring nontrivial topological characteristics, such as optical skyrmions. Conventional OAM beams, nonetheless, carry discrete integer topological charges (TCs), leading to discrete SAM states. This discrete property poses a persistent challenge for achieving continuous control of SAM. To tackle this fundamental issue, we explored fractional orbital angular momentum (FOAM) beams, whose TCs are extended from integers to fractions, to realize continuous and precise control of SAM. A direct mathematical relationship between the fractional effective TCs of FOAM beams and the orientation distributions of the SAM vector has been derived. This theoretical prediction has been experimentally verified using our home-built near-field mapping system, by which the distinct SAM distributions of surface cosine waves regulated by FOAM beams were mapped out. As a potential application, we also devised an inverse detection method to accurately measure the fractional effective TCs of FOAM, which achieved theoretical and experimental accuracies of 10 <jats:sup>−5</jats:sup> and 10 <jats:sup>−2</jats:sup> , respectively. These advancements may enhance our fundamental understanding of the SOI mechanism, and hence could create novel opportunities for light field manipulation, optical communication, and other related areas.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"92 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145454581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2025-11-07DOI: 10.1515/nanoph-2025-0339
Junhyung Lee, Sunghyun Moon, Yongchan Park, Uijoon Park, Hansol Kim, Changhyun Kim, Minho Choi, Jin-Il Lee, Hyeon Hwang, Min-Kyo Seo, Dae-Hwan Ahn, Hojoong Jung, Hyounghan Kwon
Nonlinear signal generation requires precise control of the input polarization to satisfy phase-matching conditions. Conventional polarization management using external fiber polarization controllers or bulk wave plates increases coupling complexity and can degrade polarization fidelity and conversion efficiency in nonlinear photonic systems. Here, we demonstrate on-chip polarization control in thin-film lithium niobate nonlinear photonic circuits. Integrated polarization modulators enable real-time tuning of arbitrary input polarization states and thus provide on-demand control of nonlinear conversion in a periodically poled lithium niobate waveguide. A closed-loop feedback system, which integrates auto-compensation and automatic fiber-chip alignment routines, automatically optimizes the second-harmonic generation intensity and maintains performance over extended periods despite polarization scrambling and environmental perturbations. This integrated approach reduces coupling complexity and offers a scalable route toward fully reconfigurable nonlinear photonic systems.
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