Pub Date : 2025-12-10DOI: 10.1515/nanoph-2025-0508
Wangke Yu, Yijie Shen
Spatiotemporal (ST) wave packets constitute a broad class of optical pulses whose spatial and temporal degrees of freedom cannot be treated independently. Such space-time non-separability can induce exotic physical effects such as non-diffraction, non-transverse waves, and sub or superluminal propagation. Here, a higher-order generalised family of ST modes is presented, where modal orders are proposed to enrich their ST structural complexity, analogous to spatial higher-order Gaussian modes. This framework also incorporates spatial eigenmodes and typical ST pulses (e.g., toroidal light pulses) as elementary members. The modal orders are strongly coupled to the Gouy phase, which can unveil anomalous ST Gouy-phase dynamics, including ultrafast cycle-switching evolution, ST self-healing, and sub/super-luminal propagation. We further introduce a stretch parameter that stretches the temporal envelope while keeping the Gouy-phase coefficient unchanged. This stretch invariance decouples pulse duration from modal order, allowing us to tune the few-cycle width without shifting temporal-revival positions or altering the phase/group-velocity laws. Moreover, an approach to analysing the phase velocity and group velocity of the higher-order ST modes is proposed to quantitatively characterise the sub/super-luminal effects. The method is universal for a larger group of complex structured pulses, laying the basis for both fundamental physics and advanced applications in ultrafast optics and structured light.
{"title":"Higher-order spatiotemporal wave packets with Gouy phase dynamics","authors":"Wangke Yu, Yijie Shen","doi":"10.1515/nanoph-2025-0508","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0508","url":null,"abstract":"Spatiotemporal (ST) wave packets constitute a broad class of optical pulses whose spatial and temporal degrees of freedom cannot be treated independently. Such space-time non-separability can induce exotic physical effects such as non-diffraction, non-transverse waves, and sub or superluminal propagation. Here, a higher-order generalised family of ST modes is presented, where modal orders are proposed to enrich their ST structural complexity, analogous to spatial higher-order Gaussian modes. This framework also incorporates spatial eigenmodes and typical ST pulses (e.g., toroidal light pulses) as elementary members. The modal orders are strongly coupled to the Gouy phase, which can unveil anomalous ST Gouy-phase dynamics, including ultrafast cycle-switching evolution, ST self-healing, and sub/super-luminal propagation. We further introduce a stretch parameter that stretches the temporal envelope while keeping the Gouy-phase coefficient unchanged. This stretch invariance decouples pulse duration from modal order, allowing us to tune the few-cycle width without shifting temporal-revival positions or altering the phase/group-velocity laws. Moreover, an approach to analysing the phase velocity and group velocity of the higher-order ST modes is proposed to quantitatively characterise the sub/super-luminal effects. The method is universal for a larger group of complex structured pulses, laying the basis for both fundamental physics and advanced applications in ultrafast optics and structured light.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"39 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711406","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 : 2025-12-10DOI: 10.1515/nanoph-2025-0510
Xiaomin Lv, Ze Wang, Tianyu Xu, Chen Yang, Xing Jin, Binbin Nie, Du Qian, Yanwu Liu, Kaixuan Zhu, Bo Ni, Qihuang Gong, Fang Bo, Qi-Fan Yang
Thin-film lithium niobate (TFLN) has enabled efficient on-chip electro-optic modulation and frequency conversion for information processing and precision measurement. Extending these capabilities with optical frequency combs unlocks massively parallel operations and coherent optical-to-microwave transduction, which are achievable in TFLN microresonators via Kerr microcombs. However, fully integrated Kerr microcombs directly driven by semiconductor lasers remain elusive, which has delayed integration of these technologies. Here, we demonstrate electrically pumped TFLN Kerr microcombs without optical amplification. With optimized laser-to-chip coupling and optical quality factors, we generate soliton microcombs at a 200 GHz repetition frequency with an optical span of 180 nm using only 25 mW of pump power. Moreover, self-injection locking enables turnkey initiation and substantially narrows the laser linewidth. Our work provides integrated comb sources for TFLN-based communicational, computational, and metrological applications.
{"title":"Electrically pumped soliton microcombs on thin-film lithium niobate","authors":"Xiaomin Lv, Ze Wang, Tianyu Xu, Chen Yang, Xing Jin, Binbin Nie, Du Qian, Yanwu Liu, Kaixuan Zhu, Bo Ni, Qihuang Gong, Fang Bo, Qi-Fan Yang","doi":"10.1515/nanoph-2025-0510","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0510","url":null,"abstract":"Thin-film lithium niobate (TFLN) has enabled efficient on-chip electro-optic modulation and frequency conversion for information processing and precision measurement. Extending these capabilities with optical frequency combs unlocks massively parallel operations and coherent optical-to-microwave transduction, which are achievable in TFLN microresonators via Kerr microcombs. However, fully integrated Kerr microcombs directly driven by semiconductor lasers remain elusive, which has delayed integration of these technologies. Here, we demonstrate electrically pumped TFLN Kerr microcombs without optical amplification. With optimized laser-to-chip coupling and optical quality factors, we generate soliton microcombs at a 200 GHz repetition frequency with an optical span of 180 nm using only 25 mW of pump power. Moreover, self-injection locking enables turnkey initiation and substantially narrows the laser linewidth. Our work provides integrated comb sources for TFLN-based communicational, computational, and metrological applications.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"28 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711407","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 : 2025-12-09DOI: 10.1515/nanoph-2025-0498
Hyungchul Park, Beomjoon Chae, Hyunsoo Jang, Sunkyu Yu, Xianji Piao
Exploiting alternative physical dimensions beyond the spatial domain has been intensively explored to improve the scalability in photonic computing. One approach leverages dynamical systems for time-domain computation, enabling universal and reconfigurable unitary operations. Although this method yields O ( N ) scaling in both device footprint and gate count, the required computation time increases by O ( N2 ), which hinders practical implementation due to limitations in quality factors and modulation speeds of optical elements. Here, we propose time-parallelized photonic lattices that achieve O ( N ) time scalability while preserving the O ( N ) spatial scaling. We devise a pseudospinor buffer operation that temporally stores the optical information, thereby enabling parallel unitary computation. The proposed method not only mitigates the requirement for high-quality factors but also provides robustness against a broad range of defects, demonstrating the feasibility of time-domain photonic computation.
{"title":"Scalable unitary computing using time-parallelized photonic lattices","authors":"Hyungchul Park, Beomjoon Chae, Hyunsoo Jang, Sunkyu Yu, Xianji Piao","doi":"10.1515/nanoph-2025-0498","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0498","url":null,"abstract":"Exploiting alternative physical dimensions beyond the spatial domain has been intensively explored to improve the scalability in photonic computing. One approach leverages dynamical systems for time-domain computation, enabling universal and reconfigurable unitary operations. Although this method yields <jats:italic>O</jats:italic> ( <jats:italic>N</jats:italic> ) scaling in both device footprint and gate count, the required computation time increases by <jats:italic>O</jats:italic> ( <jats:italic>N</jats:italic> <jats:sup>2</jats:sup> ), which hinders practical implementation due to limitations in quality factors and modulation speeds of optical elements. Here, we propose time-parallelized photonic lattices that achieve <jats:italic>O</jats:italic> ( <jats:italic>N</jats:italic> ) time scalability while preserving the <jats:italic>O</jats:italic> ( <jats:italic>N</jats:italic> ) spatial scaling. We devise a pseudospinor buffer operation that temporally stores the optical information, thereby enabling parallel unitary computation. The proposed method not only mitigates the requirement for high-quality factors but also provides robustness against a broad range of defects, demonstrating the feasibility of time-domain photonic computation.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"20 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145703990","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 : 2025-12-09DOI: 10.1515/nanoph-2025-2000
Takuo Tanaka, Wakana Kubo
{"title":"Editorial on special issue “The 11th International Conference on Surface Plasmon Photonics (SPP11)”","authors":"Takuo Tanaka, Wakana Kubo","doi":"10.1515/nanoph-2025-2000","DOIUrl":"https://doi.org/10.1515/nanoph-2025-2000","url":null,"abstract":"","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"7 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145711409","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 : 2025-12-08DOI: 10.1515/nanoph-2025-0421
Rostislav Řepa, Michal Horák, Tomáš Šikola, Vlastimil Křápek
Plasmonic antennas exploit localized surface plasmons to shape, confine, and enhance electromagnetic fields with subwavelength resolution. The field enhancement is contributed to by various effects, such as the inherent surface localization of plasmons or the plasmonic lightning-rod effect. Inspired by nanofocusing observed for propagating plasmons, we test the hypothesis that plasmonic antennas with a large cross-section represent a large charge reservoir, enabling large induced charge and field enhancement. Our study reveals that a large charge reservoir is accompanied by large radiative losses, which are the dominant factor, resulting in a low field enhancement.
{"title":"Charge reservoir as a design concept for plasmonic antennas","authors":"Rostislav Řepa, Michal Horák, Tomáš Šikola, Vlastimil Křápek","doi":"10.1515/nanoph-2025-0421","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0421","url":null,"abstract":"Plasmonic antennas exploit localized surface plasmons to shape, confine, and enhance electromagnetic fields with subwavelength resolution. The field enhancement is contributed to by various effects, such as the inherent surface localization of plasmons or the plasmonic lightning-rod effect. Inspired by nanofocusing observed for propagating plasmons, we test the hypothesis that plasmonic antennas with a large cross-section represent a large charge reservoir, enabling large induced charge and field enhancement. Our study reveals that a large charge reservoir is accompanied by large radiative losses, which are the dominant factor, resulting in a low field enhancement.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"3 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145703943","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 : 2025-12-08DOI: 10.1515/nanoph-2025-0409
Qianli Qiu, Kang Li, Dongjie Zhou, Yuyang Zhang, Jinguo Zhang, Zongkun Zhang, Yan Sun, Lei Zhou, Ning Dai, Junhao Chu, Jiaming Hao
The long wavelength infrared (LWIR) range (8–14 µm) is crucial for thermal radiation detection, necessitating effective camouflage against advanced infrared technologies. Conventional camouflage approaches often rely on complicated photonic structures, facing significant implementation challenges. This study introduces a novel polarization-insensitive and angle-robust metacoating emitter for LWIR camouflage, inversely designed through a deep neural network (DNN) framework. The DNN framework facilitates the automatic optimization of the metacoating’s structural and material parameters. The resulting emitter achieves an average emissivity of 0.96 covering the LWIR range and a low emissivity of 0.25 in the other mid-infrared (MIR) region. Enhanced electromagnetic wave localization and energy dissipation, driven by high-lossy materials like bismuth and titanium, contribute to these properties. Infrared imaging confirms the emitter’s superior camouflage performance, maintain effectiveness at incident angle up to 70° while exhibiting strong polarization independence. This inverse-designed metacoating demonstrates significant potential to advance infrared camouflage technology, providing robust countermeasures against modern, wide-angle, and polarization-sensitive detection systems.
{"title":"Lithography-free subwavelength metacoatings for high thermal radiation background camouflage empowered by deep neural network","authors":"Qianli Qiu, Kang Li, Dongjie Zhou, Yuyang Zhang, Jinguo Zhang, Zongkun Zhang, Yan Sun, Lei Zhou, Ning Dai, Junhao Chu, Jiaming Hao","doi":"10.1515/nanoph-2025-0409","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0409","url":null,"abstract":"The long wavelength infrared (LWIR) range (8–14 µm) is crucial for thermal radiation detection, necessitating effective camouflage against advanced infrared technologies. Conventional camouflage approaches often rely on complicated photonic structures, facing significant implementation challenges. This study introduces a novel polarization-insensitive and angle-robust metacoating emitter for LWIR camouflage, inversely designed through a deep neural network (DNN) framework. The DNN framework facilitates the automatic optimization of the metacoating’s structural and material parameters. The resulting emitter achieves an average emissivity of 0.96 covering the LWIR range and a low emissivity of 0.25 in the other mid-infrared (MIR) region. Enhanced electromagnetic wave localization and energy dissipation, driven by high-lossy materials like bismuth and titanium, contribute to these properties. Infrared imaging confirms the emitter’s superior camouflage performance, maintain effectiveness at incident angle up to 70° while exhibiting strong polarization independence. This inverse-designed metacoating demonstrates significant potential to advance infrared camouflage technology, providing robust countermeasures against modern, wide-angle, and polarization-sensitive detection systems.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"4 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145697019","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 : 2025-12-08DOI: 10.1515/nanoph-2025-0479
Stefanos Fr. Koufidis, Zeki Hayran, Francesco Monticone, John B. Pendry, Martin W. McCall
Optical analog computing enables powerful functionalities, including spatial differentiation, image processing, and ultrafast linear operations. Yet, most existing approaches rely on resonant or periodic structures, whose performance is strongly wavelength-dependent, imposing bandwidth limitations and demanding stringent fabrication tolerances. Here, to address some of these challenges, we introduce a highly tunable platform for optical processing, composed of two cascaded uniform slabs exhibiting both circular and linear birefringence, whose response exhibits features relevant to optical processing without relying on resonances. Specifically, using a coupled-wave theory framework we show that sharp reflection minima, referred to as spectral holes, emerge from destructive interference between counter-propagating circularly polarized waves in uniform birefringent slabs, and can be engineered solely through parameter tuning without requiring any spatial periodicity. When operated in the negative-refraction regime enabled by giant chirality, the interference response acquires a highly parabolic form around the reflection minimum, giving rise to a polarization-selective Laplacian-like operator that performs accurate spatial differentiation over a broad spatial-frequency range. This functionality is demonstrated through an edge-detection proof of concept. The required material parameters align closely with recent experimental demonstrations of giant, tunable chirality via meta-optics, presenting a promising pathway towards compact and reconfigurable platforms for all-optical pattern recognition and image restoration.
{"title":"Chirality-driven all-optical image differentiation","authors":"Stefanos Fr. Koufidis, Zeki Hayran, Francesco Monticone, John B. Pendry, Martin W. McCall","doi":"10.1515/nanoph-2025-0479","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0479","url":null,"abstract":"Optical analog computing enables powerful functionalities, including spatial differentiation, image processing, and ultrafast linear operations. Yet, most existing approaches rely on resonant or periodic structures, whose performance is strongly wavelength-dependent, imposing bandwidth limitations and demanding stringent fabrication tolerances. Here, to address some of these challenges, we introduce a highly tunable platform for optical processing, composed of two cascaded uniform slabs exhibiting both circular and linear birefringence, whose response exhibits features relevant to optical processing without relying on resonances. Specifically, using a coupled-wave theory framework we show that sharp reflection minima, referred to as spectral holes, emerge from destructive interference between counter-propagating circularly polarized waves in uniform birefringent slabs, and can be engineered solely through parameter tuning without requiring any spatial periodicity. When operated in the negative-refraction regime enabled by giant chirality, the interference response acquires a highly parabolic form around the reflection minimum, giving rise to a polarization-selective Laplacian-like operator that performs accurate spatial differentiation over a broad spatial-frequency range. This functionality is demonstrated through an edge-detection proof of concept. The required material parameters align closely with recent experimental demonstrations of giant, tunable chirality via meta-optics, presenting a promising pathway towards compact and reconfigurable platforms for all-optical pattern recognition and image restoration.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"133 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145696981","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 : 2025-12-08DOI: 10.1515/nanoph-2025-0504
Tetsuhito Omori, Kentaro Iwami
Metasurface holography is a promising technology for next-generation 3D displays, however, conventional approaches for full-colorization have faced challenges. Wavelength multiplexing based on spatial segmentation/interleaving inevitably reduces pixel density, while techniques reliant on the Pancharatnam–Berry (PB) phase are inherently polarization-dependent and have a theoretical efficiency limit of 50 %. In this work, we propose and experimentally demonstrate a design strategy that overcomes these limitations. The core of our approach is a single, polarization-independent meta-atom, realized with cross-shaped nanopillars made of silicon nitride (SiN), which enables the simultaneous and independent phase control over the three primary colors required for faithful 3D image reconstruction. This single-unit strategy surpasses the pixel density limitations of wavelength multiplexing. Furthermore, we combine this innovation with crosstalk elimination via spatial division of target 3D images and precise angle correction to ensure high-fidelity, superimposed reconstruction. Experimentally, we have successfully reconstructed high-definition, noise-free 3D full-color holograms. Our work resolves the critical limitations of pixel density and polarization dependence in metasurface holography, providing a robust pathway toward practical, high-performance holographic displays.
{"title":"Wavelength- and angle-multiplexed full-color 3D metasurface hologram","authors":"Tetsuhito Omori, Kentaro Iwami","doi":"10.1515/nanoph-2025-0504","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0504","url":null,"abstract":"Metasurface holography is a promising technology for next-generation 3D displays, however, conventional approaches for full-colorization have faced challenges. Wavelength multiplexing based on spatial segmentation/interleaving inevitably reduces pixel density, while techniques reliant on the Pancharatnam–Berry (PB) phase are inherently polarization-dependent and have a theoretical efficiency limit of 50 %. In this work, we propose and experimentally demonstrate a design strategy that overcomes these limitations. The core of our approach is a single, polarization-independent meta-atom, realized with cross-shaped nanopillars made of silicon nitride (SiN), which enables the simultaneous and independent phase control over the three primary colors required for faithful 3D image reconstruction. This single-unit strategy surpasses the pixel density limitations of wavelength multiplexing. Furthermore, we combine this innovation with crosstalk elimination via spatial division of target 3D images and precise angle correction to ensure high-fidelity, superimposed reconstruction. Experimentally, we have successfully reconstructed high-definition, noise-free 3D full-color holograms. Our work resolves the critical limitations of pixel density and polarization dependence in metasurface holography, providing a robust pathway toward practical, high-performance holographic displays.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"65 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145703941","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 : 2025-12-08DOI: 10.1515/nanoph-2025-0495
Alberto Santonocito, Alessio Gabbani, Barbara Patrizi, Guido Toci, Francesco Pineider
Static metasurfaces offer precise control over light but lack reconfigurability, limiting their use in dynamic applications. Introducing tunability via external stimuli, such as magnetic fields, enables active control of their optical response, broadening their functionality. In this computational study, we present the design of a metal–dielectric–metal magnetoplasmonic metasurface with improved magnetic field tunability, surpassing the magneto-optical response of unstructured ferromagnetic materials. This improvement arises from the synergistic effect of localized plasmon excitation, surface lattice resonance, and Fabry–Pérot cavity modes. The design approach presented here consists in matching the characteristic resonance frequencies of the three phenomena by iteratively adjusting the structural parameters of the metasurface: nanostructure size, lattice period, and cavity layer thickness. This optimization led to a substantial enhancement in the reflectance modulation induced by an external magnetic field, with the overall contrast exceeding that of an unstructured cavity by more than an order of magnitude across various regions of the visible to near-infrared spectrum, under relatively low magnetic fields. This unique capability makes the system a promising tool for magnetic field-sensitive optical modulation of reflected light intensity, with potential applications as a laser amplitude modulator.
{"title":"Synergistic enhancement of magneto-optical response in cobalt-based metasurfaces via plasmonic, lattice, and cavity modes","authors":"Alberto Santonocito, Alessio Gabbani, Barbara Patrizi, Guido Toci, Francesco Pineider","doi":"10.1515/nanoph-2025-0495","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0495","url":null,"abstract":"Static metasurfaces offer precise control over light but lack reconfigurability, limiting their use in dynamic applications. Introducing tunability via external stimuli, such as magnetic fields, enables active control of their optical response, broadening their functionality. In this computational study, we present the design of a metal–dielectric–metal magnetoplasmonic metasurface with improved magnetic field tunability, surpassing the magneto-optical response of unstructured ferromagnetic materials. This improvement arises from the synergistic effect of localized plasmon excitation, surface lattice resonance, and Fabry–Pérot cavity modes. The design approach presented here consists in matching the characteristic resonance frequencies of the three phenomena by iteratively adjusting the structural parameters of the metasurface: nanostructure size, lattice period, and cavity layer thickness. This optimization led to a substantial enhancement in the reflectance modulation induced by an external magnetic field, with the overall contrast exceeding that of an unstructured cavity by more than an order of magnitude across various regions of the visible to near-infrared spectrum, under relatively low magnetic fields. This unique capability makes the system a promising tool for magnetic field-sensitive optical modulation of reflected light intensity, with potential applications as a laser amplitude modulator.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"11 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145703946","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}
Most light-emitting devices based on quantum-confined structures are commonly utilized as electrically injected devices. However, the electric-field-dependent energy band gap induced by the quantum confinement Stark effect (QCSE) usually hinders the realization of frequency-stable laser devices. This is because the change in the energy band gap, which also means the corresponding change in the photon energy, will result in an electric-field-dependent frequency. Here, we propose a novel approach to mitigate this electric-field-dependent variation in the energy band gap by employing a gradient quantum system. In this system, the energy band edges are inclined due to the action of the indium (In)-segregation effect. This special design can effectively weaken the changes in the band profile associated with the electric field effect and counteract the electric-field-dependent band gap variations within the active region to a certain extent. Experimental studies indicate that the energy band gap of this gradient quantum system remains almost unchanged (<18.9 μeV cm 2 /A) even under a relatively strong applied electric field. Meanwhile, compared with the traditional GaAs quantum well, the efficiency improvement in the band gap stability of our nanowire–well gradient system is 64.1 % and 70.6 % for the TE and TM polarization modes, respectively, which suggests that our proposed gradient quantum structure can significantly mitigate the electric-field-induced change in the energy band gap. This achievement is of great significance for advancing the development of high-performance frequency-stable laser devices in some advanced fields, such as quantum sensing systems and optical communications.
大多数基于量子约束结构的发光器件通常用作电注入器件。然而，由量子约束斯塔克效应（QCSE）引起的电场相关能带隙通常阻碍了频率稳定激光器件的实现。这是因为能带隙的变化，也意味着光子能量的相应变化，将导致与电场相关的频率。在这里，我们提出了一种新的方法，通过使用梯度量子系统来减轻这种电场依赖的能带隙变化。在该体系中，由于铟（In）偏析效应的作用，能带边缘发生倾斜。这种特殊的设计可以有效地减弱与电场效应相关的带廓变化，并在一定程度上抵消有源区内电场相关的带隙变化。实验研究表明，在较强的外加电场作用下，该梯度量子系统的能带几乎保持不变（18.9 μeV cm 2 /A）。同时，与传统的GaAs量子阱相比，我们的纳米线-阱梯度系统在TE和TM极化模式下的带隙稳定性效率分别提高了64.1%和70.6%，这表明我们提出的梯度量子结构可以显著减轻电场引起的带隙变化。这一成果对于推进量子传感系统、光通信等先进领域高性能稳频激光器件的发展具有重要意义。
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