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17 pages, 1970 KB

Open AccessArticle

Tunable Structural Color in Au-Based One-Dimensional Hyperbolic Metamaterials

by Ricardo Téllez-Limón, René I. Rodríguez-Beltrán, Fernando López-Rayón, Mauricio Gómez-Robles, Katie Figueroa-Guardiola, Jesús E. Chávez-Padua, Victor Coello and Rafael Salas-Montiel

Nanomaterials 2025, 15(24), 1898; https://doi.org/10.3390/nano15241898 - 17 Dec 2025

Viewed by 406

Abstract

Structural coloration arising from nanoscale light–matter interactions has emerged as a key research area in nanophotonics. Among the various materials investigated, noble metals—particularly gold—play a central role due to their well-defined plasmonic response and chemical stability, but their structural coloring typically requires complex [...] Read more.

Structural coloration arising from nanoscale light–matter interactions has emerged as a key research area in nanophotonics. Among the various materials investigated, noble metals—particularly gold—play a central role due to their well-defined plasmonic response and chemical stability, but their structural coloring typically requires complex and highly engineered nanostructures. However, modern photonic technologies demand scalable approaches to produce structural colors that can be finely tuned. In this contribution, we experimentally and numerically demonstrate the fine tunability of structural color in gold-based one-dimensional hyperbolic metamaterials (1D-HMMs) by varying their structural parameters: number of layers (N), period (T), and filling fraction (p). Our results show that variations in N lead to changes in luminance with minimal shifts in chromaticity, while variations in T introduce moderate color shifts without affecting luminance. In contrast, changes in p produce the largest modifications in chromaticity, though the trend is non-monotonic and less predictable. These findings highlight the potential of 1D-HMMs for achieving finely controlled gold-based coloration for advanced photonic technologies. Full article

(This article belongs to the Topic Nanomaterials for Photonics and Optoelectronics: Practical Applications and Advances)

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12 pages, 3019 KB

Open AccessArticle

Ultra-Compact, High-Efficiency Vertical Meta-Grating Couplers for Meta-Photonic Integrated Circuits

by Hang Cheng, Jiagui Wu, Yue Wang, Chongchong Ran, Haitang Li, Yu Wang, Yuanhui Li, Sen Zhang, Chunhui Wang and Junbo Yang

Nanomaterials 2025, 15(8), 583; https://doi.org/10.3390/nano15080583 - 11 Apr 2025

Cited by 4 | Viewed by 1754

Abstract

Vertical meta-grating couplers (VMGCs), while essential for flexible spatial beam coupling in meta-photonic integrated circuits (MPICs), suffer from inherently low coupling efficiency that hinders broader applications. In this study, we introduce an improved adjoint optimization method with high computational efficiency and excellent optimization [...] Read more.

Vertical meta-grating couplers (VMGCs), while essential for flexible spatial beam coupling in meta-photonic integrated circuits (MPICs), suffer from inherently low coupling efficiency that hinders broader applications. In this study, we introduce an improved adjoint optimization method with high computational efficiency and excellent optimization effectiveness. Utilizing this method, we demonstrate an ultra-compact single-polarization VMGC achieving 81.57% coupling efficiency with a 92 nm 3 dB bandwidth, and a dual-polarization beam-splitting coupler with over 52% coupling efficiency for both polarizations, a 3 dB bandwidth exceeding 60 nm, an ultra-high extinction ratio of over 26.4 dB, and negligible polarization dependent loss at 1550 nm. To the best of our knowledge, this achievement represents the best simulation record to date for a perfect vertical coupler without bottom reflectors. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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9 pages, 4899 KB

Open AccessCommunication

Plasmonic Metalens to Generate an Airy Beam

by Citlalli T. Sosa-Sánchez and Ricardo Téllez-Limón

Nanomaterials 2023, 13(18), 2576; https://doi.org/10.3390/nano13182576 - 17 Sep 2023

Cited by 5 | Viewed by 2259

Abstract

Airy beams represent an important type of non-diffracting beams—they are the only non-diffracting wave in one dimension, and thus they can be produced with a cylindrical geometry that modifies a wavefront in one dimension. In this paper, we show the design of a [...] Read more.

Airy beams represent an important type of non-diffracting beams—they are the only non-diffracting wave in one dimension, and thus they can be produced with a cylindrical geometry that modifies a wavefront in one dimension. In this paper, we show the design of a cylindrical plasmonic metalens consisting of an array of nanoslits in a gold thin layer that modulates the phase of a Gaussian beam to generate an airy beam propagating in free space. Based on the numerical results, we show that it is possible to generate an airy beam by only matching the phase of wavefronts coming out from the array of gold nanoslits to the airy beam phase at plane

z = 0

. We numerically demonstrate that the airy beam exhibits bending over propagation and self-healing properties. The transmission efficiency is around 60%. The simplicity of the proposed structure open new perspectives in the design of flat metasurfaces for light-focusing applications. Full article

(This article belongs to the Section Nanophotonics Materials and Devices)

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43 pages, 11260 KB

Open AccessEditor’s ChoiceReview

Recent Advances in Metaphotonic Biosensors

by Dang Du Nguyen, Seho Lee and Inki Kim

Biosensors 2023, 13(6), 631; https://doi.org/10.3390/bios13060631 - 7 Jun 2023

Cited by 17 | Viewed by 6197

Abstract

Metaphotonic devices, which enable light manipulation at a subwavelength scale and enhance light–matter interactions, have been emerging as a critical pillar in biosensing. Researchers have been attracted to metaphotonic biosensors, as they solve the limitations of the existing bioanalytical techniques, including the sensitivity, [...] Read more.

Metaphotonic devices, which enable light manipulation at a subwavelength scale and enhance light–matter interactions, have been emerging as a critical pillar in biosensing. Researchers have been attracted to metaphotonic biosensors, as they solve the limitations of the existing bioanalytical techniques, including the sensitivity, selectivity, and detection limit. Here, we briefly introduce types of metasurfaces utilized in various metaphotonic biomolecular sensing domains such as refractometry, surface-enhanced fluorescence, vibrational spectroscopy, and chiral sensing. Further, we list the prevalent working mechanisms of those metaphotonic bio-detection schemes. Furthermore, we summarize the recent progress in chip integration for metaphotonic biosensing to enable innovative point-of-care devices in healthcare. Finally, we discuss the impediments in metaphotonic biosensing, such as its cost effectiveness and treatment for intricate biospecimens, and present a prospect for potential directions for materializing these device strategies, significantly influencing clinical diagnostics in health and safety. Full article

(This article belongs to the Special Issue Advanced Optical Sensing Techniques for Applications in Biomedicine)

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10 pages, 968 KB

Open AccessArticle

Integrated Optical Filters with Hyperbolic Metamaterials

by Mas-ud A. Abdulkareem, Fernando López-Rayón, Citlalli T. Sosa-Sánchez, Ramsés E. Bautista González, Maximino L. Arroyo Carrasco, Marycarmen Peña-Gomar, Victor Coello and Ricardo Téllez-Limón

Nanomaterials 2023, 13(4), 759; https://doi.org/10.3390/nano13040759 - 17 Feb 2023

Cited by 8 | Viewed by 3695

Abstract

The growing development of nanotechnology requires the design of new devices that integrate different functionalities at a reduced scale. For on-chip applications such as optical communications or biosensing, it is necessary to selectively transmit a portion of the electromagnetic spectrum. This function is [...] Read more.

The growing development of nanotechnology requires the design of new devices that integrate different functionalities at a reduced scale. For on-chip applications such as optical communications or biosensing, it is necessary to selectively transmit a portion of the electromagnetic spectrum. This function is performed by the so-called band-pass filters. While several plasmonic nanostructures of complex fabrication integrated to optical waveguides have been proposed, hyperbolic metamaterials remain almost unexplored for the design of integrated band-pass filters at optical wavelengths. By making use of the effective medium theory and finite integration technique, in this contribution we numerically study an integrated device consisting of a one-dimensional hyperbolic metamaterial placed on top of a photonic waveguide. The results show that the filling fraction, period, and number of layers modify the spectral response of the device, but not for type II and effective metal metamaterials. For the proposed Au-TiO₂ multilayered system, the filter operates at a wavelength of 760 nm, spectral bandwidth of 100 nm and transmission efficiency above 40%. The designed devices open new perspectives for the development of integrated band-pass filters of small scale for on-chip integrated optics applications. Full article

(This article belongs to the Special Issue Nanophotonics and Integrated Optics Devices)

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11 pages, 4217 KB

Open AccessArticle

Plasmonic-Induced Transparencies in an Integrated Metaphotonic System

by Fernando López-Rayón, Maximino L. Arroyo Carrasco, René I. Rodríguez-Beltrán, Rafael Salas-Montiel and Ricardo Téllez-Limón

Nanomaterials 2022, 12(10), 1701; https://doi.org/10.3390/nano12101701 - 16 May 2022

Cited by 5 | Viewed by 3139

Abstract

In this contribution, we numerically demonstrate the generation of plasmonic transparency windows in the transmission spectrum of an integrated metaphotonic device. The hybrid photonic–plasmonic structure consists of two rectangular-shaped gold nanoparticles fully embedded in the core of a multimode dielectric optical waveguide, with [...] Read more.

In this contribution, we numerically demonstrate the generation of plasmonic transparency windows in the transmission spectrum of an integrated metaphotonic device. The hybrid photonic–plasmonic structure consists of two rectangular-shaped gold nanoparticles fully embedded in the core of a multimode dielectric optical waveguide, with their major axis aligned to the electric field lines of transverse electric guided modes. We show that these transparencies arise from different phenomena depending on the symmetry of the guided modes. For the TE

_{0}

mode, the quadrupolar and dipolar plasmonic resonances of the nanoparticles are weakly coupled, and the transparency window is due to the plasmonic analogue of electromagnetically induced transparency. For the TE

_{1}

mode, the quadrupolar and dipolar resonances of the nanoparticles are strongly coupled, and the transparency is originated from the classical analogue of the Autler–Townes effect. This analysis contributes to the understanding of plasmonic transparency windows, opening new perspectives in the design of on-chip devices for optical communications, sensing, and signal filtering applications. Full article

(This article belongs to the Special Issue Nanophotonics and Integrated Optics Devices)

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13 pages, 6174 KB

Open AccessArticle

Double-Focusing Gradient-Index Lens with Elastic Bragg Mirror for Highly Efficient Energy Harvesting

by Jeonghoon Park, Geon Lee, Dongwoo Lee, Miso Kim and Junsuk Rho

Nanomaterials 2022, 12(6), 1019; https://doi.org/10.3390/nano12061019 - 21 Mar 2022

Cited by 17 | Viewed by 3715

Abstract

The applicability of piezoelectric energy harvesting is increasingly investigated in the field of renewable energy. In improving harvester efficiency, manipulating elastic waves through a geometric configuration as well as upgrading harvester elements is important. Periodic structures, such as phononic crystals and metamaterials, are [...] Read more.

The applicability of piezoelectric energy harvesting is increasingly investigated in the field of renewable energy. In improving harvester efficiency, manipulating elastic waves through a geometric configuration as well as upgrading harvester elements is important. Periodic structures, such as phononic crystals and metamaterials, are extensively employed to control elastic waves and enhance harvesting performance, particularly in terms of wave localization and focusing. In this study, we propose a double-focusing flexural energy harvesting platform consisting of a gradient-index lens and elastic Bragg mirror. Based on the design process, the frequency and time response of the harvesting platform are analyzed. The results indicate that the output voltage and power calculated at 1800

Ω

are 7.9 and 62 times higher than those observed in the bare plate, respectively. Even when compared to the existing gradient-index system, they are 1.5 and 2.3 times higher, respectively. These findings can facilitate the usage of periodic structures as geometric stimuli to significantly enhance harvesting performance. Full article

(This article belongs to the Special Issue Properties and Applications of Metamaterials)

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14 pages, 3257 KB

Open AccessFeature PaperArticle

Enhancement of Luminous Intensity Emission from Incoherent LED Light Sources within the Detection Angle of 10° Using Metalenses

by Hanlyun Cho, Heonyeong Jeong, Younghwan Yang, Trevon Badloe and Junsuk Rho

Nanomaterials 2022, 12(1), 153; https://doi.org/10.3390/nano12010153 - 1 Jan 2022

Cited by 7 | Viewed by 4806

Abstract

In this work, we present metalenses (MLs) designed to enhance the luminous intensity of incoherent light-emitting diodes (LEDs) within the detection angles of 0° and 10°. The detection angle of 0° refers to the center of the LED. Because the light emitted from [...] Read more.

In this work, we present metalenses (MLs) designed to enhance the luminous intensity of incoherent light-emitting diodes (LEDs) within the detection angles of 0° and 10°. The detection angle of 0° refers to the center of the LED. Because the light emitted from LEDs is incoherent and expressed as a surface light source, they are numerically described as a set of point sources and calculated using incoherent summation. The titanium dioxide (TiO₂) and amorphous silicon (a-Si) nanohole meta-atoms are designed; however, the full 2π phase coverage is not reached. Nevertheless, because the phase modulation at the edge of the ML is important, an ML is successfully designed. The typical phase profile of the ML enhances the luminous intensity at the center, and the phase profile is modified to increase the luminous intensity in the target detection angle region. Far field simulations are conducted to calculate the luminous intensity after 25 m of propagation. We demonstrate an enhancement of the luminous intensity at the center by 8551% and 2115% using TiO₂ and a-Si MLs, respectively. Meanwhile, the TiO₂ and a-Si MLs with the modified phase profiles enhance the luminous intensity within the detection angle of 10° by 263% and 30%, respectively. Full article

(This article belongs to the Special Issue Metalens: Applications and Manufacturing)

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12 pages, 2331 KB

Open AccessFeature PaperEditor’s ChoiceOpinion

Next-Generation Imaging Techniques: Functional and Miniaturized Optical Lenses Based on Metamaterials and Metasurfaces

by Dasol Lee, Minkyung Kim and Junsuk Rho

Micromachines 2021, 12(10), 1142; https://doi.org/10.3390/mi12101142 - 23 Sep 2021

Cited by 11 | Viewed by 5119

Abstract

A variety of applications using miniaturized optical lenses can be found among rapidly evolving technologies. From smartphones and cameras in our daily life to augmented and virtual reality glasses for the recent trends of the untact era, miniaturization of optical lenses permits the [...] Read more.

A variety of applications using miniaturized optical lenses can be found among rapidly evolving technologies. From smartphones and cameras in our daily life to augmented and virtual reality glasses for the recent trends of the untact era, miniaturization of optical lenses permits the development of many types of compact devices. Here, we highlight the importance of ultrasmall and ultrathin lens technologies based on metamaterials and metasurfaces. Focusing on hyperlenses and metalenses that can replace or be combined with the existing conventional lenses, we review the state-of-art of research trends and discuss their limitations. We also cover applications that use miniaturized imaging devices. The miniaturized imaging devices are expected to be an essential foundation for next-generation imaging techniques. Full article

(This article belongs to the Section A：Physics)

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