Nanophotonics最新文献

{"title":"Surface plasmon polariton–enhanced upconversion luminescence for biosensing applications","authors":"Duc Le, Marjut Kreivi, Sanna Aikio, Noora Heinilehto, Teemu Sipola, Jarno Petäjä, Tian-Long Guo, Matthieu Roussey, Jussi Hiltunen","doi":"10.1515/nanoph-2024-0247","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0247","url":null,"abstract":"Upconversion luminescence (UCL) has great potential for highly sensitive biosensing due to its unique wavelength shift properties. The main limitation of UCL is its low quantum efficiency, which is typically compensated using low-noise detectors and high-intensity excitation. In this work, we demonstrate surface plasmon polariton (SPP)-enhanced UCL for biosensing applications. SPPs are excited by using a gold grating. The gold grating is optimized to match the SPP resonance with the absorption wavelength of upconverting nanoparticles (UCNPs). Functionalized UCNPs conjugated with antibodies are immobilized on the surface of the fabricated gold grating. We achieve an UCL enhancement up to 65 times at low excitation power density. This enhancement results from the increase in the absorption cross section of UCNPs caused by the SPP coupling on the grating surface. Computationally, we investigated a slight quenching effect in the emission process with UCNPs near gold surfaces. The experimental observations were in good agreement with the simulation results. The work enables UCL-based assays with reduced excitation intensity that are needed, for example, in scanning-free imaging.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"148 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142084767","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}

{"title":"Two-dimensional flat-band solitons in superhoneycomb lattices","authors":"Shuang Shen, Yiqi Zhang, Yaroslav V. Kartashov, Yongdong Li, Vladimir V. Konotop","doi":"10.1515/nanoph-2024-0299","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0299","url":null,"abstract":"Flat-band periodic materials are characterized by a linear spectrum containing at least one band where the propagation constant remains nearly constant irrespective of the Bloch momentum across the Brillouin zone. These materials provide a unique platform for investigating phenomena related to light localization. Meantime, the interaction between flat-band physics and nonlinearity in continuous systems remains largely unexplored, particularly in continuous systems where the band flatness deviates slightly from zero, in contrast to simplified discrete systems with exactly flat bands. Here, we use a continuous superhoneycomb lattice featuring a flat band in its spectrum to theoretically and numerically introduce a range of stable flat-band solitons. These solutions encompass fundamental, dipole, multi-peak, and even vortex solitons. Numerical analysis demonstrates that these solitons are stable in a broad range of powers. They do not bifurcate from the flat band and can be analyzed using Wannier function expansion leading to their designation as <jats:italic>Wannier solitons</jats:italic>. These solitons showcase novel possibilities for light localization and transmission within nonlinear flat-band systems.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"34 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141899515","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}

{"title":"Broadband mode exchanger based on subwavelength Y-junctions","authors":"Raquel Fernández de Cabo, Alejandro Sánchez-Sánchez, Yijun Yang, Daniele Melati, Carlos Alonso-Ramos, Aitor V. Velasco, David González-Andrade","doi":"10.1515/nanoph-2024-0291","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0291","url":null,"abstract":"Multimode silicon photonics, leveraging mode-division multiplexing technologies, offers significant potential to increase capacity of large-scale multiprocessing systems for on-chip optical interconnects. These technologies have implications not only for telecom and datacom applications, but also for cutting-edge fields such as quantum and nonlinear photonics. Thus, the development of compact, low-loss and low-crosstalk multimode devices, in particular mode exchangers, is crucial for effective on-chip mode manipulation. This work introduces a novel mode exchanger that exploits the properties of subwavelength grating metamaterials and symmetric Y-junctions, achieving low losses and crosstalk over a broad bandwidth and a compact size of only 6.5 µm × 2.6 µm. The integration of SWG nanostructures in our design enables precise control of mode exchange through different propagation constants in the arms and metamaterial, and takes advantage of dispersion engineering to broaden the operating bandwidth. Experimental characterization demonstrates, to the best of our knowledge, the broadest operational bandwidth covering from 1,420 nm to 1,620 nm, with measured losses as low as 0.5 dB and extinction ratios higher than 10 dB. Enhanced performance is achieved within a 149 nm bandwidth (1,471–1,620 nm), showing measured losses below 0.4 dB and extinction ratios greater than 18 dB.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"157 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141899408","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}

{"title":"Clearing a path for light through non-Hermitian media","authors":"Utsav D. Dave, Gaurang R. Bhatt, Janderson R. Rodrigues, Ipshita Datta, Michal Lipson","doi":"10.1515/nanoph-2024-0140","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0140","url":null,"abstract":"The performance of all active photonic devices today is greatly limited by loss. Here, we show that one can engineer a low loss path in a metal-clad lossy multi-mode waveguide while simultaneously achieving high-performance active photonic devices. We leverage non-Hermitian systems operating beyond the exceptional point to enable the redistribution of losses in a multi-mode photonic waveguide. Consequently, our multi-mode waveguide offers low propagation losses for fundamental mode while other higher order modes experience prohibitively high losses. Furthermore, we show an application of this non-Hermitian waveguide platform in designing power-efficient thermo-optic phase shifters with significantly faster response times than conventional silicon-based thermo-optic phase shifters. Our device achieves a propagation loss of less than 0.02 dB μm<jats:sup>−1</jats:sup> for our non-Hermitian waveguide-based phase shifters with high performance efficiency of <jats:italic>P</jats:italic> <jats:sub> <jats:italic>π</jats:italic> </jats:sub> ⋅ <jats:italic>τ</jats:italic> = 19.1 mW μs. In addition, our phase shifters have significantly faster response time (rise/fall time), <jats:italic>τ</jats:italic> ≈ 1.4 μs, compared to traditional silicon based thermo-optic phase shifters.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"52 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141899407","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}

{"title":"Flat band fine-tuning and its photonic applications","authors":"Carlo Danieli, Alexei Andreanov, Daniel Leykam, Sergej Flach","doi":"10.1515/nanoph-2024-0135","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0135","url":null,"abstract":"Flat bands – single-particle energy bands – in tight-binding lattices, aka networks, have attracted attention due to the presence of macroscopic degeneracies and their sensitivity to perturbations. They support compact localized eigenstates protected by destructive interference. This makes them natural candidates for emerging exotic phases and unconventional orders. In this review we consider the recently proposed systematic ways to construct flat band networks based on symmetries or fine-tuning. We then discuss how the construction methods can be further extended, adapted or exploited in presence of perturbations, both single-particle and many-body. This strategy has lead to the discovery of non-perturbative metal-insulator transitions, fractal phases, nonlinear and quantum caging and many-body nonergodic quantum models. We discuss what implications these results may have for the design of fine-tuned nanophotonic systems including photonic crystals, nanocavities, and metasurfaces.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"41 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880364","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}

{"title":"Enhanced vertical second harmonic generation from layered GaSe coupled to photonic crystal circular Bragg resonators","authors":"Zhuojun Liu, Bo Chen, Xuying Wang, Guixin Qiu, Qitao Cao, Dunzhao Wei, Jin Liu","doi":"10.1515/nanoph-2024-0282","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0282","url":null,"abstract":"Two-dimensional (2D) layered materials without centrosymmetry, such as GaSe, have emerged as promising novel optical materials due to large second-order nonlinear susceptibilities. However, their nonlinear responses are severely limited by the short interaction between the 2D materials and light, which should be improved by coupling them with photonic structures with strong field confinement. Here, we theoretically design photonic crystal circular Bragg gratings (CBG) based on hole gratings with a quality factor as high as <jats:italic>Q</jats:italic> = 8 × 10<jats:sup>3</jats:sup>, a mode volume as small as <jats:italic>V</jats:italic> = 1.18 (<jats:italic>λ</jats:italic>/<jats:italic>n</jats:italic>)<jats:sup>3</jats:sup>, and vertical emission of light field in silicon nitride thin film platform. Experimentally, we achieved a <jats:italic>Q</jats:italic> value up to nearly 4 × 10<jats:sup>3</jats:sup>, resulting in a 1,200-fold enhancement of second harmonic generation from GaSe flakes with a thickness of 50 nm coupling to the CBG structures under continuous-wave excitation. Our work endows silicon-based photonic platforms with significant second-order nonlinear effect, which is potentially applied in on-chip quantum light sources and nonlinear frequency conversion.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"149 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880365","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}

{"title":"Symmetry-protected bound states in the continuum on an integrated photonic platform","authors":"Qijing Lu, Ziyao Feng, Xiankai Sun","doi":"10.1515/nanoph-2024-0196","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0196","url":null,"abstract":"Bound states in the continuum (BICs) have attracted much attention in the field of nanophotonics owing to their ability to trap photons without loss. Recently, a low-refractive-index (RI) waveguide loaded on a high-RI slab structure was demonstrated to support BICs. However, strict control of structural parameters is required due to the accidental nature of those BICs. Here, we propose a novel structure consisting of two low-RI vertically coupled waveguides loaded on a high-RI slab. This structure supports symmetry-protected BICs (SP-BICs), which do not require strict control of the geometric parameters. Such SP-BICs can also possess an infinitely high quality factor in resonant structures, which can be harnessed for ultranarrow-bandwidth spatial and spectral filters. Our work opens a new way of harnessing BICs on an integrated photonic platform for realizing nanophotonic circuits and devices.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"86 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880362","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}

{"title":"Integrating deep convolutional surrogate solvers and particle swarm optimization for efficient inverse design of plasmonic patch nanoantennas","authors":"Saeed Hemayat, Sina Moayed Baharlou, Alexander Sergienko, Abdoulaye Ndao","doi":"10.1515/nanoph-2024-0195","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0195","url":null,"abstract":"Plasmonic nanoantennas with suitable far-field characteristics are of huge interest for utilization in optical wireless links, inter-/intrachip communications, LiDARs, and photonic integrated circuits due to their exceptional modal confinement. Despite its success in shaping robust antenna design theories in radio frequency and millimeter-wave regimes, conventional transmission line theory finds its validity diminished in the optical frequencies, leading to a noticeable void in a generalized theory for antenna design in the optical domain. By utilizing neural networks, and through a one-time training of the network, one can transform the plasmonic nanoantennas design into an automated, data-driven task. In this work, we have developed a multi-head deep convolutional neural network serving as an efficient inverse-design framework for plasmonic patch nanoantennas. Our framework is designed with the main goal of determining the optimal geometries of nanoantennas to achieve the desired (inquired by the designer) <jats:italic>S</jats:italic> <jats:sub>11</jats:sub> and radiation pattern simultaneously. The proposed approach preserves the one-to-many mappings, enabling us to generate diverse designs. In addition, apart from the primary fabrication limitations that were considered while generating the dataset, further design and fabrication constraints can also be applied after the training process. In addition to possessing an exceptionally rapid surrogate solver capable of predicting <jats:italic>S</jats:italic> <jats:sub>11</jats:sub> and radiation patterns throughout the entire design frequency spectrum, we are introducing what we believe to be the pioneering inverse design network. This network enables the creation of efficient plasmonic antennas while concurrently accommodating customizable queries for both <jats:italic>S</jats:italic> <jats:sub>11</jats:sub> and radiation patterns, achieving remarkable accuracy within a single network framework. Our framework is capable of designing a wide range of devices, including single band, dual band, and broadband antennas, with directivities and radiation efficiencies reaching 11.07 dBi and 75 %, respectively, for a single patch. The proposed approach has been developed as a transformative shift in the inverse design of photonics components, with its impact extending beyond antenna design, opening a new paradigm toward real-time design of application-specific nanophotonic devices.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"75 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880361","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}

{"title":"Fast and low energy-consumption integrated Fourier-transform spectrometer based on thin-film lithium niobate","authors":"Xijie Wang, Ziliang Ruan, Kaixuan Chen, Gengxin Chen, Mai Wang, Bin Chen, Liu Liu","doi":"10.1515/nanoph-2024-0219","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0219","url":null,"abstract":"Integrated miniature spectrometers have impacts in industry, agriculture, and aerospace applications due to their unique advantages in portability and energy consumption. Although existing on-chip spectrometers have achieved breakthroughs in key performance metrics, such as, a high resolution and a large bandwidth, their scanning speed and energy consumption still hinder practical applications of such devices. Here, a stationary Fourier transform spectrometer is introduced based on a Mach–Zehnder interferometer structure on thin-film lithium niobate. Long and low-loss spiral waveguides with electro-optic tuning are adopted as the optical path scanning elements with a half-wave voltage of 0.14 V. A high resolution of 2.1 nm and a spectral recovery with a bandwidth of 100 nm is demonstrated under a high-speed and high-voltage scanning in the range of −100 V to +100 V at up to 100 KHz. A low energy consumption in the μJ scale per scan is also achieved.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"130 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141880363","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}

{"title":"Substrate-induced hybridization of plasmon modes in the composite nanostructure of nanodisk array/thin film for spectrum modulation","authors":"Yuzhang Liang, Shuwen Chu, Xinran Wei, Haonan Wei, Sun Cheng, Yi Han, Wei Peng","doi":"10.1515/nanoph-2024-0159","DOIUrl":"https://doi.org/10.1515/nanoph-2024-0159","url":null,"abstract":"Hybridization coupling among plasmon modes is an effective approach to manipulate near-field properties thus optical spectral shapes of plasmonic nanostructures. Generally, mode hybridization coupling is achieved by modifying the topography and dimensions of nanostructures themselves, with few concerns about substrate-induced manipulation. Herein, we propose a composite nanostructure consisting of a gold (Au) nanodisk array and a thin Au film supported by a dielectric substrate. In this configuration, both the refractive index of the dielectric substrate and thin gold film’s thickness mediate the interaction of plasmon modes supported by upper and lower interfaces of the composite nanostructure, resulting in two hybridized plasmon modes. We systematically investigate the relationship between optical fields at the top surface of plasmon modes before and after the hybridization coupling. Specifically, the near-field amplitude at the top surface of the unhybridized modes is stronger than that of individual hybridized mode, and lower than the near-field summation of these two hybridized modes. This work not only provides a straightforward strategy for generating two plasmon modes in a nanostructure but also elucidates the variation of the optical field during the hybridization process, which is of crucial significance for applications, such as upconversion enhancement and multi-resonance sensing.","PeriodicalId":19027,"journal":{"name":"Nanophotonics","volume":"52 1","pages":""},"PeriodicalIF":7.5,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141877296","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}