Pub Date : 2025-11-25DOI: 10.1515/nanoph-2025-0453
Dominik Sidler, Carlos M. Bustamante, Franco P. Bonafé, Michael Ruggenthaler, Maxim Sukharev, Angel Rubio
Controlling chemical and material properties through strong light–matter coupling in optical cavities has gained considerable attention over the past decade. However, the underlying mechanisms remain insufficiently understood, and a significant gap persists between experimental observations and theoretical descriptions. This challenge arises from the intrinsically multiscale nature of the problem, where nonperturbative feedback occurs across different spatial and temporal scales. Collective coupling between a macroscopic ensemble of molecules and a photonic environment, such as a Fabry–Pérot cavity, can strongly influence the microscopic properties of individual molecules, while microscopic details of the ensemble in turn affect the macroscopic coupling. To address this complexity, we present an efficient computational framework that combines density-functional tight binding (density-functional tight binding ( dftb )) with finite-difference time-domain (finite-difference time domain ( fdtd )) simulations of Maxwell’s equations ( dftb + Maxwell). This approach allows for a self-consistent treatment of both the cavity and the microscopic details of the molecular ensemble. We demonstrate the potential of this method by tackling several open questions. First, we calculate nonperturbatively two-dimensional spectroscopic observables that directly connect to well-established experimental protocols. Second, we provide local, molecule-resolved information within collectively coupled ensembles, which is difficult to obtain experimentally. Third, we show how cavity designs can be optimized to target specific microscopic applications. Finally, we outline future directions to enhance the predictive power of this framework, including extensions to finite temperature, condensed phases, and correlated quantum effects. The dftb + Maxwell method enables real-time exploration of realistic chemical parameters on standard computational resources and offers a systematic approach to bridging the gap between experiment and theory.
{"title":"Density-functional tight binding meets Maxwell: unraveling the mysteries of (strong) light–matter coupling efficiently","authors":"Dominik Sidler, Carlos M. Bustamante, Franco P. Bonafé, Michael Ruggenthaler, Maxim Sukharev, Angel Rubio","doi":"10.1515/nanoph-2025-0453","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0453","url":null,"abstract":"Controlling chemical and material properties through strong light–matter coupling in optical cavities has gained considerable attention over the past decade. However, the underlying mechanisms remain insufficiently understood, and a significant gap persists between experimental observations and theoretical descriptions. This challenge arises from the intrinsically multiscale nature of the problem, where nonperturbative feedback occurs across different spatial and temporal scales. Collective coupling between a macroscopic ensemble of molecules and a photonic environment, such as a Fabry–Pérot cavity, can strongly influence the microscopic properties of individual molecules, while microscopic details of the ensemble in turn affect the macroscopic coupling. To address this complexity, we present an efficient computational framework that combines density-functional tight binding (density-functional tight binding ( <jats:sc>dftb</jats:sc> )) with finite-difference time-domain (finite-difference time domain ( <jats:sc>fdtd</jats:sc> )) simulations of Maxwell’s equations ( <jats:sc>dftb</jats:sc> + Maxwell). This approach allows for a self-consistent treatment of both the cavity and the microscopic details of the molecular ensemble. We demonstrate the potential of this method by tackling several open questions. First, we calculate nonperturbatively two-dimensional spectroscopic observables that directly connect to well-established experimental protocols. Second, we provide local, molecule-resolved information within collectively coupled ensembles, which is difficult to obtain experimentally. Third, we show how cavity designs can be optimized to target specific microscopic applications. Finally, we outline future directions to enhance the predictive power of this framework, including extensions to finite temperature, condensed phases, and correlated quantum effects. The <jats:sc>dftb</jats:sc> + Maxwell method enables real-time exploration of realistic chemical parameters on standard computational resources and offers a systematic approach to bridging the gap between experiment and theory.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"167 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145592933","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 : 2025-11-25DOI: 10.1515/nanoph-2025-0511
Diana Galiakhmetova, Nawal Mohamed, Fatima Khanom, Shakti Singh, Gennadii Piavchenko, Grigorii S. Sokolovskii, Edik Rafailov, Igor Meglinski
Topologically structured light carrying orbital angular momentum (OAM) has emerged as a powerful tool for nano-photonics and biomedical optics, yet conventional integer-charge Laguerre–Gaussian (LG) beams suffer from rotational degeneracy that limits diagnostic precision. Here, we demonstrate that conical refraction (CR) beams, specifically the Lloyd, Poggendorff, and Raman families, overcome this fundamental limitation through their inherent generation of fractional OAM states with unambiguous phase signatures. Through systematic interferometric comparison of LG ( ℓ = 3, 5) and CR beam propagation in tissues, we show that CR beams achieve superior diagnostic performance: while LG beams exhibit three-fold rotational ambiguity (4.19 rad uncertainty), Poggendorff CR beams provide phase determination with 0.08 rad precision. Both LG and CR beam families display remarkable topological resilience, preserving phase coherence as they traverse tissue samples while attaining refractive index sensitivity at the 10 −6 level, three orders of magnitude beyond conventional refractometry. Most significantly, we present the first experimental evidence that CR beams can discriminate between healthy and cancerous kidney tissues through distinct phase rotations (4.71 vs. 5.04 rad, p < 0.001) and a tenfold amplification in polarisation-induced distortion. The fractional topological charges of CR beams, ranging continuously between integer values, expand the accessible OAM phase space and enable 3.7-fold superior signal-to-noise ratio compared to LG03${text{LG}}_{0}^{3}$ measurements. These results establish CR-generated fractional OAM as the preferred modality for label-free tissue diagnostics, bridging fundamental nanophotonics with clinical applications in cancer detection and intraoperative margin assessment.
携带轨道角动量的拓扑结构光（OAM）已经成为纳米光子学和生物医学光学的有力工具，然而传统的整电荷拉盖尔-高斯（LG）光束存在旋转简并，限制了诊断精度。在这里，我们证明了锥形折射（CR）光束，特别是劳埃德、波根多夫和拉曼家族，通过其固有的具有明确相位特征的分数OAM态的产生，克服了这一基本限制。通过系统干涉比较LG （r = 3,5）和CR光束在组织中的传播，我们发现CR光束具有优越的诊断性能：LG光束具有三倍旋转模糊（4.19 rad不确定性），而Poggendorff CR光束提供0.08 rad精度的相位测定。LG和CR光束家族都显示出卓越的拓扑弹性，在穿过组织样品时保持相位相干性，同时获得10 - 6级的折射率灵敏度，比传统的折射率测量法高出三个数量级。最重要的是，我们提供了第一个实验证据，证明CR光束可以通过不同的相位旋转（4.71 vs. 5.04 rad, p < 0.001）和极化诱导畸变的十倍放大来区分健康和癌性肾脏组织。CR光束的分数阶拓扑电荷在整数之间连续变化，扩展了可访问的OAM相位空间，实现了比LG 0.3 ${text{LG}}_{0}^{3}$测量值高3.7倍的信噪比。这些结果确立了cr生成的分数OAM作为无标记组织诊断的首选方式，将基础纳米光子学与癌症检测和术中边缘评估的临床应用联系起来。
{"title":"Topological phase structures of conical refraction beams: expanding orbital angular momentum applications for nanoscale biosensing","authors":"Diana Galiakhmetova, Nawal Mohamed, Fatima Khanom, Shakti Singh, Gennadii Piavchenko, Grigorii S. Sokolovskii, Edik Rafailov, Igor Meglinski","doi":"10.1515/nanoph-2025-0511","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0511","url":null,"abstract":"Topologically structured light carrying orbital angular momentum (OAM) has emerged as a powerful tool for nano-photonics and biomedical optics, yet conventional integer-charge Laguerre–Gaussian (LG) beams suffer from rotational degeneracy that limits diagnostic precision. Here, we demonstrate that conical refraction (CR) beams, specifically the Lloyd, Poggendorff, and Raman families, overcome this fundamental limitation through their inherent generation of fractional OAM states with unambiguous phase signatures. Through systematic interferometric comparison of LG ( <jats:italic>ℓ</jats:italic> = 3, 5) and CR beam propagation in tissues, we show that CR beams achieve superior diagnostic performance: while LG beams exhibit three-fold rotational ambiguity (4.19 rad uncertainty), Poggendorff CR beams provide phase determination with 0.08 rad precision. Both LG and CR beam families display remarkable topological resilience, preserving phase coherence as they traverse tissue samples while attaining refractive index sensitivity at the 10 <jats:sup>−6</jats:sup> level, three orders of magnitude beyond conventional refractometry. Most significantly, we present the first experimental evidence that CR beams can discriminate between healthy and cancerous kidney tissues through distinct phase rotations (4.71 vs. 5.04 rad, <jats:italic>p</jats:italic> < 0.001) and a tenfold amplification in polarisation-induced distortion. The fractional topological charges of CR beams, ranging continuously between integer values, expand the accessible OAM phase space and enable 3.7-fold superior signal-to-noise ratio compared to <jats:inline-formula> <jats:alternatives> <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" overflow=\"scroll\"> <m:msubsup> <m:mrow> <m:mtext>LG</m:mtext> </m:mrow> <m:mrow> <m:mn>0</m:mn> </m:mrow> <m:mrow> <m:mn>3</m:mn> </m:mrow> </m:msubsup> </m:math> <jats:tex-math>${text{LG}}_{0}^{3}$</jats:tex-math> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" xlink:href=\"graphic/j_nanoph-2025-0511_ineq_001.png\"/> </jats:alternatives> </jats:inline-formula> measurements. These results establish CR-generated fractional OAM as the preferred modality for label-free tissue diagnostics, bridging fundamental nanophotonics with clinical applications in cancer detection and intraoperative margin assessment.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"188 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145592932","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 : 2025-11-25DOI: 10.1515/nanoph-2025-0472
Jianmin Zhang, Jian Shen, Shuxiao Wang, Zhuoyun Li, Wencheng Yue, Xin Ou, Yan Cai
Driven by the development of AI applications, optical communication systems experience an exponential surge in the demand for high data rates. Thin-film lithium niobate (TFLN) electro-optic (EO) modulators have been extensively studied and show potential for application in next-generation optical communication systems. In this paper, we present a dual-polarization (DP) TFLN EO modulator integrated based on an EO equalizer, fabricated on the lithium-niobate-on-insulator (LNOI) platform. The device consists of an 11-mm-long forward modulation section and a 4.5-mm-long reverse modulation section. It achieves a half-wave voltage (V π ) of 4 V for both Y-polarization (Y-pol) and X-polarization (X-pol), and exhibits an on-chip insertion loss of 2.5 dB for Y-pol and 2.8 dB for X-pol at a wavelength of 1,550 nm. A 3-dB EO bandwidth exceeding 110 GHz with low EO roll-off is achieved for both TE and TM modes. Furthermore, the modulator supports a data transmission rate of 512 Gbit/s in 4-level pulse amplitude modulation (PAM4) format, corresponding to 256 Gbit/s per polarization. This work demonstrates a beyond 400 G/λ solution for implementing a high-speed, and large-bandwidth modulator on a conventional LNOI platform.
{"title":"512 Gbps/λ dual-polarization thin-film lithium niobate modulators based on an electro-optic equalizer","authors":"Jianmin Zhang, Jian Shen, Shuxiao Wang, Zhuoyun Li, Wencheng Yue, Xin Ou, Yan Cai","doi":"10.1515/nanoph-2025-0472","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0472","url":null,"abstract":"Driven by the development of AI applications, optical communication systems experience an exponential surge in the demand for high data rates. Thin-film lithium niobate (TFLN) electro-optic (EO) modulators have been extensively studied and show potential for application in next-generation optical communication systems. In this paper, we present a dual-polarization (DP) TFLN EO modulator integrated based on an EO equalizer, fabricated on the lithium-niobate-on-insulator (LNOI) platform. The device consists of an 11-mm-long forward modulation section and a 4.5-mm-long reverse modulation section. It achieves a half-wave voltage (V <jats:sub>π</jats:sub> ) of 4 V for both Y-polarization (Y-pol) and X-polarization (X-pol), and exhibits an on-chip insertion loss of 2.5 dB for Y-pol and 2.8 dB for X-pol at a wavelength of 1,550 nm. A 3-dB EO bandwidth exceeding 110 GHz with low EO roll-off is achieved for both TE and TM modes. Furthermore, the modulator supports a data transmission rate of 512 Gbit/s in 4-level pulse amplitude modulation (PAM4) format, corresponding to 256 Gbit/s per polarization. This work demonstrates a beyond 400 G/λ solution for implementing a high-speed, and large-bandwidth modulator on a conventional LNOI platform.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"162 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145593454","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 : 2025-11-25DOI: 10.1515/nanoph-2025-0473
Fatemeh Davoodi
Topological photonic systems offer a robust platform for guiding light in the presence of disorder, but their interplay with quantum emitters remains a frontier for realizing strongly correlated quantum states. Here, we explore a ring-shaped Su-Schrieffer-Heeger (SSH) photonic lattice interfaced with multiple quantum emitters to control topologically protected chiral quantum dynamics. Using a full microscopic model that includes cascaded Lindblad dynamics and chiral emitter-bath couplings, we reveal how the topology of the bath mediates nonreciprocal, long-range interactions between emitters. These interactions lead to rich many-body spin phenomena, including robust coherence, directional energy transfer, captured by an effective spin Hamiltonian derived from the system’s topology. We show that topological bound states enable unidirectional emission, protect coherence against dissipation, and imprint nontrivial entanglement and mutual information patterns among the emitters. In particular, we showed that under circularly polarized excitation, the emitters not only inherit spin angular momentum from the field but also serve as transducers that coherently launch the spin-orbit-coupled topological photonic modes into the far field. Our results establish a direct bridge between topological photonic baths and emergent quantum magnetism, positioning this architecture as a promising testbed for studying chiral quantum optics, topologically protected entangled states, and long-range quantum coherence.
{"title":"From bound states to quantum spin models: chiral coherent dynamics in topological photonic rings","authors":"Fatemeh Davoodi","doi":"10.1515/nanoph-2025-0473","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0473","url":null,"abstract":"Topological photonic systems offer a robust platform for guiding light in the presence of disorder, but their interplay with quantum emitters remains a frontier for realizing strongly correlated quantum states. Here, we explore a ring-shaped Su-Schrieffer-Heeger (SSH) photonic lattice interfaced with multiple quantum emitters to control topologically protected chiral quantum dynamics. Using a full microscopic model that includes cascaded Lindblad dynamics and chiral emitter-bath couplings, we reveal how the topology of the bath mediates nonreciprocal, long-range interactions between emitters. These interactions lead to rich many-body spin phenomena, including robust coherence, directional energy transfer, captured by an effective spin Hamiltonian derived from the system’s topology. We show that topological bound states enable unidirectional emission, protect coherence against dissipation, and imprint nontrivial entanglement and mutual information patterns among the emitters. In particular, we showed that under circularly polarized excitation, the emitters not only inherit spin angular momentum from the field but also serve as transducers that coherently launch the spin-orbit-coupled topological photonic modes into the far field. Our results establish a direct bridge between topological photonic baths and emergent quantum magnetism, positioning this architecture as a promising testbed for studying chiral quantum optics, topologically protected entangled states, and long-range quantum coherence.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"34 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145592931","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 : 2025-11-24DOI: 10.1515/nanoph-2025-0413
Zhiyuan Shi, Wei Jiang, Yanqing Lu, Weihua Zhang
This study presents a super-resolution light manipulation technique in the near-field region of a silicon nanolens array in the blue spectral range using a computer-generated holography technique. It allows us to focus light into a spot below 70 nm at arbitrarily given positions within the entire lens array using modulated incident fields. To achieve this, an inverse design algorithm is developed using multiaxis high-order Gaussian beam expansion. It effectively corrects aberrations in off-axis focal spots within each nanolens unit, resulting in high-quality nanofocused beams with an extended depth of focus. By superimposing discrete nanofocused spots, we can further synthesize complex intensity patterns across multiple nanolens units, achieving an intensity profile resolution of 80 nm. This offers a promising approach for super-resolution photolithography using visible light.
{"title":"Sub-100 nm manipulation of blue light over a large field of view using Si nanolens array","authors":"Zhiyuan Shi, Wei Jiang, Yanqing Lu, Weihua Zhang","doi":"10.1515/nanoph-2025-0413","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0413","url":null,"abstract":"This study presents a super-resolution light manipulation technique in the near-field region of a silicon nanolens array in the blue spectral range using a computer-generated holography technique. It allows us to focus light into a spot below 70 nm at arbitrarily given positions within the entire lens array using modulated incident fields. To achieve this, an inverse design algorithm is developed using multiaxis high-order Gaussian beam expansion. It effectively corrects aberrations in off-axis focal spots within each nanolens unit, resulting in high-quality nanofocused beams with an extended depth of focus. By superimposing discrete nanofocused spots, we can further synthesize complex intensity patterns across multiple nanolens units, achieving an intensity profile resolution of 80 nm. This offers a promising approach for super-resolution photolithography using visible light.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"191 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145592934","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 : 2025-11-24DOI: 10.1515/nanoph-2025-0335
Jiayu Huang, Run Li, Suo Wang, Qianqian Jia, Zichuan Xiang, Jinling Yang, Jinye Li, Jianguo Liu
Erbium-doped waveguide amplifiers (EDWAs) are vital for photonic integration, yet most are built on z-cut lithium niobate, incompatible with the mainstream x-cut platform. This work presents a combined theoretical and experimental study of polarization-dependent gain in x-cut Er:LNOI. Using Judd–Ofelt theory, we analyze how crystal orientation governs TE-mode coupling to Er 3+ ions, predicting stark differences in transition strengths between α - and π -polarizations. Experiments confirm these predictions: at 1,531 nm, the absorption and emission cross sections for α -polarization are 1.8 times larger than for π -polarization. At 1,550 nm, the α -polarization shows a gain coefficient of 3.3 dB/cm versus 2.2 dB/cm for π -polarization. In the small-signal regime, the α -polarized amplifier achieves 32.01 dB signal enhancement with 11.18 dB internal net gain. With 9.1 dBm on-chip input power, it delivers 21.18 mW unsaturated output power under pumping levels exceeding 200 mW. This work demonstrates feasible optical amplification on x-cut LNOI, providing crucial support for large-scale photonic and microwave photonic systems.
{"title":"Polarization-dependent gain characterization in x-cut LNOI erbium-doped waveguide amplifiers","authors":"Jiayu Huang, Run Li, Suo Wang, Qianqian Jia, Zichuan Xiang, Jinling Yang, Jinye Li, Jianguo Liu","doi":"10.1515/nanoph-2025-0335","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0335","url":null,"abstract":"Erbium-doped waveguide amplifiers (EDWAs) are vital for photonic integration, yet most are built on z-cut lithium niobate, incompatible with the mainstream x-cut platform. This work presents a combined theoretical and experimental study of polarization-dependent gain in x-cut Er:LNOI. Using Judd–Ofelt theory, we analyze how crystal orientation governs TE-mode coupling to Er <jats:sup>3+</jats:sup> ions, predicting stark differences in transition strengths between <jats:italic>α</jats:italic> - and <jats:italic>π</jats:italic> -polarizations. Experiments confirm these predictions: at 1,531 nm, the absorption and emission cross sections for <jats:italic>α</jats:italic> -polarization are 1.8 times larger than for <jats:italic>π</jats:italic> -polarization. At 1,550 nm, the <jats:italic>α</jats:italic> -polarization shows a gain coefficient of 3.3 dB/cm versus 2.2 dB/cm for <jats:italic>π</jats:italic> -polarization. In the small-signal regime, the <jats:italic>α</jats:italic> -polarized amplifier achieves 32.01 dB signal enhancement with 11.18 dB internal net gain. With 9.1 dBm on-chip input power, it delivers 21.18 mW unsaturated output power under pumping levels exceeding 200 mW. This work demonstrates feasible optical amplification on x-cut LNOI, providing crucial support for large-scale photonic and microwave photonic systems.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"1 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145583261","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}
Meta-optics have opened new possibilities for portable, high-performance microscopy, offering ultrathin and highly customizable wavefront control in scenarios where bulky optics limit adoption. Here, we use this capability to overcome the long-standing challenges of Fourier ptychography (FP), a powerful computational technique for wide-field, high-resolution quantitative phase imaging that traditionally depends on large optical elements and extensive angle scanning. Our compact meta-FP platform combines a 4-f metalens system for imaging miniaturization with a programmable thin-film transistor (TFT) panel to provide stable, angle-diverse plane-wave illumination without mechanical movement. To further accelerate imaging, we introduce a residual convolutional neural network (RCNN) model trained via transfer learning on conventional FP datasets, which allows for single-shot inference of high-resolution phase from low-resolution inputs. Experimental validations demonstrate nearly twofold resolution improvement (7.81 µm–3.91 µm), accurate quantitative phase recovery on phase standards with errors below 10 %, and dry-mass estimation of H1975 cells with an average deviation of approximately 12 %, while the best-performing regions exhibit deviations below 0.5 %. This integration of metasurface optics and artificial intelligence-driven reconstruction provides a promising pathway for fast and compact FP microscopy with applications in live-cell imaging, microfluidic monitoring, and point-of-care diagnostics.
元光学为便携式、高性能显微镜开辟了新的可能性，在笨重的光学限制采用的情况下，提供超薄和高度可定制的波前控制。在这里，我们利用这种能力来克服傅立叶平面摄影（FP）的长期挑战，FP是一种强大的计算技术，用于宽视场，高分辨率定量相位成像，传统上依赖于大光学元件和广角扫描。我们紧凑的meta-FP平台结合了用于成像小型化的4-f超透镜系统和可编程薄膜晶体管（TFT）面板，提供稳定的、角度多样的平面波照明，而无需机械运动。为了进一步加速成像，我们引入了一个残差卷积神经网络（RCNN）模型，该模型通过在传统FP数据集上的迁移学习进行训练，该模型允许从低分辨率输入中单次推断高分辨率相位。实验验证表明，分辨率提高了近两倍（7.81 μ m - 3.91 μ m），在相位标准上精确定量相位恢复，误差低于10%，H1975细胞的干质量估计平均偏差约为12%，而表现最好的区域的偏差低于0.5%。这种超表面光学和人工智能驱动重建的集成为快速和紧凑的FP显微镜提供了一条有前途的途径，可用于活细胞成像，微流体监测和即时诊断。
{"title":"Metasurface-based Fourier ptychographic microscopy","authors":"Cheng Hung Chu, Hao-Pin Chiu, Cheng Yu, Yuan-Chung Cheng, Ching-En Lin, Sunil Vyas, Yuan Luo","doi":"10.1515/nanoph-2025-0416","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0416","url":null,"abstract":"Meta-optics have opened new possibilities for portable, high-performance microscopy, offering ultrathin and highly customizable wavefront control in scenarios where bulky optics limit adoption. Here, we use this capability to overcome the long-standing challenges of Fourier ptychography (FP), a powerful computational technique for wide-field, high-resolution quantitative phase imaging that traditionally depends on large optical elements and extensive angle scanning. Our compact meta-FP platform combines a 4-f metalens system for imaging miniaturization with a programmable thin-film transistor (TFT) panel to provide stable, angle-diverse plane-wave illumination without mechanical movement. To further accelerate imaging, we introduce a residual convolutional neural network (RCNN) model trained via transfer learning on conventional FP datasets, which allows for single-shot inference of high-resolution phase from low-resolution inputs. Experimental validations demonstrate nearly twofold resolution improvement (7.81 µm–3.91 µm), accurate quantitative phase recovery on phase standards with errors below 10 %, and dry-mass estimation of H1975 cells with an average deviation of approximately 12 %, while the best-performing regions exhibit deviations below 0.5 %. This integration of metasurface optics and artificial intelligence-driven reconstruction provides a promising pathway for fast and compact FP microscopy with applications in live-cell imaging, microfluidic monitoring, and point-of-care diagnostics.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"29 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145592935","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 : 2025-11-24DOI: 10.1515/nanoph-2025-0474
Santiago A. Gomez, Emmi K. Pohjolainen, Dmitry Morozov, Ville Tiainen, J. Jussi Toppari, Gerrit Groenhof
Cucurbit[7]uril molecules form non-covalent host – guest complexes with small molecular dyes. In addition, cucurbit[7]uril can also bind gold nanoparticles on gold surfaces with a 0.9 nm gap, creating plasmonic nanocavities for the dyes, with extreme confinement of the electromagnetic field. For methylene blue in such cavities, single molecule strong coupling was inferred from a complete disappearance of a characteristic shoulder in its spectrum, attributed to dimer removal. Yet, the shoulder’s origin remains debated. Using atomistic simulations, we show that it arises from both dimerization and vibronic progression. While cucurbit[7]uril binding removes the dimer contribution, vibronic progression persists. As this conflicts with previous reports, we also measured the spectra. In line with our computations, the shoulder remains visible when cucurbit[7]uril binds methylene blue. These results clarify the spectral features and pave the way for atomistic models of single-molecule strong coupling in nanoparticle-on-mirror cavities.
{"title":"Disentangling the absorption lineshape of methylene blue for nanocavity strong coupling","authors":"Santiago A. Gomez, Emmi K. Pohjolainen, Dmitry Morozov, Ville Tiainen, J. Jussi Toppari, Gerrit Groenhof","doi":"10.1515/nanoph-2025-0474","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0474","url":null,"abstract":"Cucurbit[7]uril molecules form non-covalent host – guest complexes with small molecular dyes. In addition, cucurbit[7]uril can also bind gold nanoparticles on gold surfaces with a 0.9 nm gap, creating plasmonic nanocavities for the dyes, with extreme confinement of the electromagnetic field. For methylene blue in such cavities, single molecule strong coupling was inferred from a complete disappearance of a characteristic shoulder in its spectrum, attributed to dimer removal. Yet, the shoulder’s origin remains debated. Using atomistic simulations, we show that it arises from both dimerization and vibronic progression. While cucurbit[7]uril binding removes the dimer contribution, vibronic progression persists. As this conflicts with previous reports, we also measured the spectra. In line with our computations, the shoulder remains visible when cucurbit[7]uril binds methylene blue. These results clarify the spectral features and pave the way for atomistic models of single-molecule strong coupling in nanoparticle-on-mirror cavities.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"13 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145583262","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 : 2025-11-22DOI: 10.1515/nanoph-2025-0475
Keijiro Suzuki, Ryotaro Konoike, Siim Heinsalu, Shu Namiki, Hitoshi Kawashima, Kazuhiro Ikeda
Silicon photonics switches are emerging as a key technology for realizing energy-efficient networks, spanning from intra data center to wafer-scale interconnections. This review focuses on recent developments and prospects of silicon photonics switches operating in the O-band, which is widely used in computing networks designed for artificial intelligence and machine learning applications. We first review our recent works on O-band silicon photonics switches fabricated by 300-mm silicon photonics technology. Specifically, we have expanded the port count of our O-band switches from 8 × 8 to 32 × 32 implemented with double Mach–Zehnder switch elements for a broad operating bandwidth. This switch achieved a 70-nm bandwidth for a crosstalk of less than −20 dB, and an average on-chip loss of 11.8 dB. Next, we discuss switch topologies optimized for wafer-scale interconnection. Conventional switch topologies typically have their input and output ports at opposite ends of the switch matrix, respectively, which poses challenges of long propagation distances and many waveguide intersections for off-chip planar waveguide routing to connect xPUs on substrate. To address this, we propose a topology where input and output ports are placed adjacently. An O-band 8 × 8 switch based on this topology was fabricated and experimentally demonstrated. Finally, we discuss the prospects and challenges of silicon photonic switches. Key issues include insertion loss, switching speed, crosstalk and operating bandwidth, and polarization dependence. These aspects are examined with reference to reports from other research groups, highlighting both current limitations and potential directions for further improvement.
{"title":"Large-scale silicon photonics switches for AI/ML interconnections based on a 300-mm CMOS pilot line","authors":"Keijiro Suzuki, Ryotaro Konoike, Siim Heinsalu, Shu Namiki, Hitoshi Kawashima, Kazuhiro Ikeda","doi":"10.1515/nanoph-2025-0475","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0475","url":null,"abstract":"Silicon photonics switches are emerging as a key technology for realizing energy-efficient networks, spanning from intra data center to wafer-scale interconnections. This review focuses on recent developments and prospects of silicon photonics switches operating in the O-band, which is widely used in computing networks designed for artificial intelligence and machine learning applications. We first review our recent works on O-band silicon photonics switches fabricated by 300-mm silicon photonics technology. Specifically, we have expanded the port count of our O-band switches from 8 × 8 to 32 × 32 implemented with double Mach–Zehnder switch elements for a broad operating bandwidth. This switch achieved a 70-nm bandwidth for a crosstalk of less than −20 dB, and an average on-chip loss of 11.8 dB. Next, we discuss switch topologies optimized for wafer-scale interconnection. Conventional switch topologies typically have their input and output ports at opposite ends of the switch matrix, respectively, which poses challenges of long propagation distances and many waveguide intersections for off-chip planar waveguide routing to connect xPUs on substrate. To address this, we propose a topology where input and output ports are placed adjacently. An O-band 8 × 8 switch based on this topology was fabricated and experimentally demonstrated. Finally, we discuss the prospects and challenges of silicon photonic switches. Key issues include insertion loss, switching speed, crosstalk and operating bandwidth, and polarization dependence. These aspects are examined with reference to reports from other research groups, highlighting both current limitations and potential directions for further improvement.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"8 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145567130","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 : 2025-11-22DOI: 10.1515/nanoph-2025-0415
Xingye Yang, Alexander Antonov, Haiyang Hu, Andreas Tittl
Bound states in the continuum (BICs) provide exceptional light confinement due to their inherent decoupling from radiative channels. Small symmetry breaking transforms BIC into quasi-BIC (qBIC) that couples to free-space radiation enabling ultra-high-quality-factor (Q-factor) resonances desirable for refractive index (RI) sensing. In practical implementations, geometric asymmetry is typically employed. However, since the radiative loss remains fixed once fabricated, such metasurfaces exhibit only a horizontal shift of the resonance spectrum in RI sensing, without modification of its overall shape. Here, we demonstrate a permittivity-asymmetric qBIC (ε-qBIC) metasurface, which encodes environmental refractive index variations directly into the asymmetry factor, resulting in an index response involving both resonance wavelength shift and modulation variation. In addition to exhibiting a competitive transmittance sensitivity of ∼5,300 %/RIU under single-wavelength conditions, the ε -qBIC design provides a substantially improved linear response. Specifically, the linear window area of its sensing data distribution, calculated as the integrated wavelength region where the linearity parameter remains above the preset threshold, is 104 times larger than that of the geometry-asymmetric qBIC (g-qBIC), enabling more robust and reliable single-wavelength signal readout. Additionally, numerical results reveal that environmental permittivity asymmetry can optically restore the g-qBIC to a state with ultra-high-Q (over 10 7 ), approaching the BIC condition. Unlike traditional BICs, which are typically inaccessible once perturbed, the permittivity-restored BIC becomes accessible through environmental perturbations. These findings suggest an alternative design strategy for developing high-performance photonic devices for practical sensing applications.
{"title":"Permittivity-asymmetric qBIC metasurfaces for refractive index sensing","authors":"Xingye Yang, Alexander Antonov, Haiyang Hu, Andreas Tittl","doi":"10.1515/nanoph-2025-0415","DOIUrl":"https://doi.org/10.1515/nanoph-2025-0415","url":null,"abstract":"Bound states in the continuum (BICs) provide exceptional light confinement due to their inherent decoupling from radiative channels. Small symmetry breaking transforms BIC into quasi-BIC (qBIC) that couples to free-space radiation enabling ultra-high-quality-factor (Q-factor) resonances desirable for refractive index (RI) sensing. In practical implementations, geometric asymmetry is typically employed. However, since the radiative loss remains fixed once fabricated, such metasurfaces exhibit only a horizontal shift of the resonance spectrum in RI sensing, without modification of its overall shape. Here, we demonstrate a permittivity-asymmetric qBIC (ε-qBIC) metasurface, which encodes environmental refractive index variations directly into the asymmetry factor, resulting in an index response involving both resonance wavelength shift and modulation variation. In addition to exhibiting a competitive transmittance sensitivity of ∼5,300 %/RIU under single-wavelength conditions, the <jats:italic>ε</jats:italic> -qBIC design provides a substantially improved linear response. Specifically, the linear window area of its sensing data distribution, calculated as the integrated wavelength region where the linearity parameter remains above the preset threshold, is 104 times larger than that of the geometry-asymmetric qBIC (g-qBIC), enabling more robust and reliable single-wavelength signal readout. Additionally, numerical results reveal that environmental permittivity asymmetry can optically restore the g-qBIC to a state with ultra-high-Q (over 10 <jats:sup>7</jats:sup> ), approaching the BIC condition. Unlike traditional BICs, which are typically inaccessible once perturbed, the permittivity-restored BIC becomes accessible through environmental perturbations. These findings suggest an alternative design strategy for developing high-performance photonic devices for practical sensing applications.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"179 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2025-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145567112","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}
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