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Deep learning enabled inverse design in nanophotonics
摘要： Deep learning has become the dominant approach in artificial intelligence to solve complex data-driven problems. Originally applied almost exclusively in computer-science areas such as image analysis and nature language processing, deep learning has rapidly entered a wide variety of scientific fields including physics, chemistry and material science. Very recently, deep neural networks have been introduced in the field of nanophotonics as a powerful way of obtaining the nonlinear mapping between the topology and composition of arbitrary nanophotonic structures and their associated functional properties. In this paper, we have discussed the recent progress in the application of deep learning to the inverse design of nanophotonic devices, mainly focusing on the three existing learning paradigms of supervised-, unsupervised-, and reinforcement learning. Deep learning forward modelling i.e. how artificial intelligence learns how to solve Maxwell’s equations, is also discussed, along with an outlook of this rapidly evolving research area.
关键词： forward modelling,inverse design,nanophotonics,artificial intelligence,metamaterials,machine learning
更新于2025-09-23 15:19:57
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Active control of narrowband total absorption based on terahertz hybrid Dirac semimetal-graphene metamaterials
摘要： A narrowband total absorber consists of a single layer of graphene, Photoactive Silicon and bulk Dirac semimetal (BDS) and has been studied in three different ways for light absorption control without changing the geometry of the structure. Numerical simulation results show that the total absorption is achieved in the narrow spectral range by the critical coupling achieved by the guided resonance, and the results are in good agreement with the coupled mode theory (CMT). Interestingly, this device exhibits exceptional polarization insensitivity and excellent absorption stability over a range of incident angles. In addition, the extremely remarkable sensing performance is more conducive to the application of bio-chemical sensors. In this article, we propose that this work achieves a significant enhancement of the interaction of light and matter in single-layer graphene without graphene plasmon response. This simple and easily fabricated narrowband total absorption structure has outstanding potential applications in the design of modulators, filters and photodetectors.
关键词： metamaterials,narrowband,absorption,critical coupling
更新于2025-09-23 15:19:57
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Special Issue: New Horizon of Plasmonics and Metamaterials
摘要： Plasmonics and metamaterials are growing fields that consistently produce new technologies for controlling electromagnetic waves. Many important advances in both fundamental knowledge and practical applications have been achieved in conjunction with a wide range of materials, structures and wavelengths, from the ultraviolet to the microwave regions of the spectrum. In addition to this remarkable progress across many different fields, much of this research shares many of the same underlying principles, and so significant synergy is expected. This Special Issue introduces the recent advances in plasmonics and metamaterials and discusses various applications, while addressing a wide range of topics in order to explore the new horizons emerging for such research.
关键词： metasurfaces,infrared sensors,plasmonics,metamaterials,polarization control
更新于2025-09-23 15:19:57
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Negative Effective Mass in Plasmonic Systems
摘要： We report the negative e?ective mass (density) metamaterials based on the electro-mechanical coupling exploiting plasma oscillations of a free electron gas. The negative mass appears as a result of the vibration of a metallic particle with a frequency of ω, which is close the frequency of the plasma oscillations of the electron gas m2 relative to the ionic lattice m1. The plasma oscillations are represented with the elastic spring k2 = ω2 pm2, where ωp is the plasma frequency. Thus, the metallic particle vibrated with the external frequency ω is described by the e?ective mass me f f = m1 + ω2 p m2 ω2 p ?ω2 , which is negative when the frequency ω approaches ωp from above. The idea is exempli?ed with two conducting metals, namely Au and Li.
关键词： negative e?ective mass,metamaterials,low frequency plasmons,plasma oscillations
更新于2025-09-23 15:19:57
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Vertically Aligned Ag <sub/><i>x</i> </sub> Au <sub/> 1a?? <i>x</i> </sub> Alloyed Nanopillars Embedded in ZnO as Nanoengineered Low-Loss Hybrid Plasmonic Metamaterials
摘要： Hybrid plasmonic metamaterials offer a pathway to exotic properties and technologically important applications including subdiffraction imaging and plasmonic energy harvesting. Challenges remain towards practical application including high absorption losses of noble metals and tedious growth / fabrication processes. In this work, a self-assembled hybrid plasmonic metamaterial consisting of anisotropic AgxAu1-x alloy nanopillars embedded in a ZnO matrix has been successfully grown. Chemical composition of the nanoalloy was determined to be Ag61Au39. The microstructure and optical properties arising from ZnO-Ag61Au39 alloyed hybrid systems were investigated and compared with that of the ZnO-Ag particle-in-matrix nanocomposite and the ZnO-Au vertically aligned nanocomposite. ZnO-Ag61Au39 hybrid system demonstrates anisotropic morphology, excellent epitaxial quality, and enhanced optical properties including surface plasmon resonance, hyperbolic dispersion, low absorption losses, and numerous epsilon-near zero permittivity points, making it a promising candidate for practical applications of hybrid plasmonic metamaterials.
关键词： oxide-metal hybrid material,plasmonics,nanoalloy,metamaterials,vertically aligned nanocomposite
更新于2025-09-23 15:19:57
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[IEEE 2019 International Conference on Smart Systems and Inventive Technology (ICSSIT) - Tirunelveli, India (2019.11.27-2019.11.29)] 2019 International Conference on Smart Systems and Inventive Technology (ICSSIT) - Power Quality Enhancement of a Photovoltaic Based Micro Grid System Using Optimized Fuzzy Controller with SAPF
摘要： We investigate terahertz quantum cascade lasers with a dense array of active micropillars forming the gain medium. Depending on the size of these pillars relative to the emission wavelength different optical regimes are identified. For pillar dimensions on the order of the emission wavelength, a photonic crystal resonator is created. Single mode emission is observed at high symmetry points of the photonic band structure. The selection mechanism of the favored laser mode is studied by analyzing the gain enhancement effect for eigenmodes with a low group velocity and a large mode confinement of the electric field energy in the micropillars. Subwavelength micropillar arrays constitute a photonic metamaterial, which can be described using an effective medium approximation. Similar to a bulk laser ridge, the array forms a Fabry–Pérot resonator that is defined by the boundaries of the array. From the longitudinal mode spacing, we derive an effective group index of the pillar medium. Limitations in terms of minimum filling factors and waveguide losses for the realization of subwavelength micropillar and nanowire array terahertz quantum cascade lasers are investigated.
关键词： optical metamaterials,terahertz,optical waveguides,Photonic crystals,quantum cascade lasers
更新于2025-09-23 15:19:57
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Graphene Plasmonic Fractal Metamaterials for Broadband Photodetectors
摘要： Metamaterials have recently established a new paradigm for enhanced light absorption in state-of-the-art photodetectors. Here, we demonstrate broadband, highly efficient, polarization-insensitive, and gate-tunable photodetection at room temperature in a novel metadevice based on gold/graphene Sierpinski carpet plasmonic fractals. We observed an unprecedented internal quantum efficiency up to 100% from the near-infrared to the visible range with an upper bound of optical detectivity of 1011 Jones and a gain up to 106, which is a fingerprint of multiple hot carriers photogenerated in graphene. Also, we show a 100-fold enhanced photodetection due to highly focused (up to a record factor of |e/e0| ≈ 20 for graphene) electromagnetic fields induced by electrically tunable multimodal plasmons, spatially localized in self-similar fashion on the metasurface. Our findings give direct insight into the physical processes governing graphene plasmonic fractal metamaterials. the proposed structure represents a promising route for the realization of a broadband, compact, and active platform for future optoelectronic devices including multiband bio/chemical and light sensors.
关键词： graphene,metamaterials,plasmonic fractals,gate-tunable,photodetectors,polarization-insensitive,broadband
更新于2025-09-23 15:19:57
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Mie Scattering in the Macroscopic Response and the Photonic Bands of Metamaterials
摘要： Herein, a general approach for the numerical calculation of the effective dielectric tensor of metamaterials is presented, and it is shown that the formalism may be used to study metamaterials beyond the long-wavelength limit. A system composed of high-refractive-index cylindrical inclusions is considered, and it is shown that the method reproduces the Mie resonant features and photonic band structure obtained from a multiple scattering approach, hence opening the possibility to study arbitrarily complex geometries for the design of resonance-based negative refractive metamaterials at optical wavelengths.
关键词： Mie resonances,nonlocal optics,metamaterials,homogenization
更新于2025-09-23 15:19:57
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Deep Learning for the Inverse Design of Mid-Infrared Graphene Plasmons
摘要： We theoretically investigate the plasmonic properties of mid-infrared graphene-based metamaterials and apply deep learning of a neural network for the inverse design. These artificial structures have square periodic arrays of graphene plasmonic resonators deposited on dielectric thin films. Optical spectra vary significantly with changes in structural parameters. To validate our theoretical approach, we carry out finite difference time domain simulations and compare computational results with theoretical calculations. Quantitatively good agreements among theoretical predictions, simulations, and previous experiments allow us to employ this proposed theoretical model to generate reliable data for training and testing deep neural networks. By merging the pre-trained neural network with the inverse network, we implement calculations for inverse design of the graphene-based metameterials. We also discuss the limitation of the data-driven approach.
关键词： inverse design,plasmonics,deep learning,graphene,metamaterials
更新于2025-09-23 15:19:57
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ELECTRIC QUADRUPOLARIZABILITY OF A SOURCE-DRIVEN DIELECTRIC SPHERE
摘要： Since both metamaterials composed of artificial molecules (inclusions in a host material) and natural molecular materials at optical and greater frequencies can exhibit significant electric quadrupolarization as well as electric and magnetic dipolarization, we determine the passive, causal electric quadrupolarizability for a spherically symmetric molecule, namely a dielectric sphere it is found that two electric quadrupolarizability constants are generally required to characterize the electric quadrupolar response of the sphere, with one of the constants multiplying the divergence of the applied electric field. For source-free fields, such as the fields of the eigenmodes of an electric quadrupolar array, the local electric field illuminating each inclusion is solenoidal, the constitutive relation is characterized by just one quadrupolarizability constant, and the electric quadrupolarization becomes traceless. It is also found that the electric quadrupolarization becomes very large and effectively traceless near the resonant frequencies of electrically small plasmonic spheres with negative permittivity and for somewhat larger spheres with positive permittivity.
关键词： metamaterials,electric quadrupolarization,plasmonic spheres,dielectric sphere,source-driven applied fields
更新于2025-09-23 15:19:57