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12 pages, 5607 KiB

Open AccessArticle

Tunable Dual-Mode Resonant Excitation of Dumbbell-Shaped Structures in the Mid-Infrared Band

by Tao Jiang, Yafei Li, Zhuangzhuang Xu, Xike Qian, Rui Shi, Xiufei Li, Meng Wang and Ze Li

Nanomaterials 2025, 15(15), 1181; https://doi.org/10.3390/nano15151181 - 31 Jul 2025

Abstract

Metasurfaces have drawn extensive research attention for their unique optical properties and vast application potential. Among the various resonant modes induced in metasurfaces, BIC and electric anapole modes stand out as particularly interesting due to their distinctive physical characteristics. In this work, we designed and investigated novel dimeric dumbbell-shaped metasurfaces incorporating two independently tunable asymmetric parameters. This structural innovation enables the simultaneous excitation of both electric anapole and QBIC modes under normally incident MIR illumination. More importantly, by adjusting these two asymmetric parameters, one can independently tune the resonance peaks of the two modes, thereby overcoming the performance limits of conventional single-peak modulation. This metasurface design demonstrates outstanding performance for dielectric environment-sensing applications. We conducted a comprehensive investigation of the sensing sensitivity for dumbbell-shaped metasurfaces of various geometries. Our simulation results show that the circular-shaped configuration achieved high sensitivity, reaching 20,930 GHz/RIU. This work offers a novel design paradigm for multi-mode control and functionalization of metasurface structures. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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13 pages, 3457 KiB

Open AccessArticle

Efficient Excitation and Tuning of Multi-Fano Resonances with High Q-Factor in All-Dielectric Metasurfaces

by Yunyan Wang, Chen Zhou, Yiping Huo, Pengfei Cui, Meina Song, Tong Liu, Chen Zhao, Zuxiong Liao, Zhongyue Zhang and You Xie

Nanomaterials 2022, 12(13), 2292; https://doi.org/10.3390/nano12132292 - 4 Jul 2022

Cited by 11 | Viewed by 2898

Abstract

Exciting Fano resonance can improve the quality factor (Q-factor) and enhance the light energy utilization rate of optical devices. However, due to the large inherent loss of metals and the limitation of phase matching, traditional optical devices based on surface plasmon resonance cannot obtain a larger Q-factor. In this study, a silicon square-hole nano disk (SHND) array device is proposed and studied numerically. The results show that, by breaking the symmetry of the SHND structure and transforming an ideal bound state in the continuum (BIC) with an infinite Q-factor into a quasi-BIC with a finite Q-factor, three Fano resonances can be realized. The calculation results also show that the three Fano resonances with narrow linewidth can produce significant local electric and magnetic field enhancements: the highest Q-factor value reaches 35,837, and the modulation depth of those Fano resonances can reach almost 100%. Considering these properties, the SHND structure realizes multi-Fano resonances with a high Q-factor, narrow line width, large modulation depth and high near-field enhancement, which could provide a new method for applications such as multi-wavelength communications, lasing, and nonlinear optical devices. Full article

(This article belongs to the Special Issue Plasmon Assisted Near-Field Manipulation and Photocatalysis)

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10 pages, 3120 KiB

Open AccessArticle

Optical Anapole Modes in Gallium Phosphide Nanodisk with Forked Slits for Electric Field Enhancement

by Jingwei Lv, He Zhang, Chao Liu, Zao Yi, Famei Wang, Haiwei Mu, Xianli Li, Tao Sun and Paul K. Chu

Nanomaterials 2021, 11(6), 1490; https://doi.org/10.3390/nano11061490 - 4 Jun 2021

Cited by 12 | Viewed by 3070

Abstract

High refractive index dielectric nanostructures represent a new frontier in nanophotonics, and the unique semiconductor characteristics of dielectric systems make it possible to enhance electric fields by exploiting this fundamental physical phenomenon. In this work, the scattered radiation spectral features and field-enhanced interactions of gallium phosphide disks with forked slits at anapole modes are investigated systematically by numerical and multipole decomposition analyses. Additional enhancement of the electric field is achieved by opening the forked slits to create high-intensity hot spots inside the disk, and nearby molecules can access these hot spots directly. The results reveal a novel approach for near-field engineering such as electric field localization, nonlinear optics, and optical detection. Full article

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13 pages, 914 KiB

Open AccessArticle

Anapole Modes in Hollow Nanocuboid Dielectric Metasurfaces for Refractometric Sensing

by José Francisco Algorri, Dimitrios C. Zografopoulos, Antonio Ferraro, Braulio García-Cámara, Ricardo Vergaz, Romeo Beccherelli and José Manuel Sánchez-Pena

Nanomaterials 2019, 9(1), 30; https://doi.org/10.3390/nano9010030 - 27 Dec 2018

Cited by 72 | Viewed by 6130

Abstract

This work proposes the use of the refractive index sensitivity of non-radiating anapole modes of high-refractive-index nanoparticles arranged in planar metasurfaces as a novel sensing principle. The spectral position of anapole modes excited in hollow silicon nanocuboids is first investigated as a function of the nanocuboid geometry. Then, nanostructured metasurfaces of periodic arrays of nanocuboids on a glass substrate are designed. The metasurface parameters are properly selected such that a resonance with ultrahigh Q-factor, above one million, is excited at the target infrared wavelength of

1.55

µm. The anapole-induced resonant wavelength depends on the refractive index of the analyte superstratum, exhibiting a sensitivity of up to 180 nm/RIU. Such values, combined with the ultrahigh Q-factor, allow for refractometric sensing with very low detection limits in a broad range of refractive indices. Besides the sensing applications, the proposed device can also open new venues in other research fields, such as non-linear optics, optical switches, and optical communications. Full article

(This article belongs to the Special Issue Dielectric Nanophotonics and Their Applications)

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9 pages, 1088 KiB

Open AccessArticle

Near-Field Coupling and Mode Competition in Multiple Anapole Systems

by Valerio Mazzone, Juan Sebastian Totero Gongora and Andrea Fratalocchi

Appl. Sci. 2017, 7(6), 542; https://doi.org/10.3390/app7060542 - 24 May 2017

Cited by 28 | Viewed by 7696

Abstract

All-dielectric metamaterials are a promising platform for the development of integrated photonics applications. In this work, we investigate the mutual coupling and interaction of an ensemble of anapole states in silicon nanoparticles. Anapoles are intriguing non-radiating states originated by the superposition of internal multipole components which cancel each other in the far-field. While the properties of anapole states in single nanoparticles have been extensively studied, the mutual interaction and coupling of several anapole states have not been characterized. By combining first-principles simulations and analytical results, we demonstrate the transferring of anapole states across an ensemble of nanoparticles, opening to the development of advanced integrated devices and robust waveguides relying on non-radiating modes. Full article

(This article belongs to the Special Issue Guided-Wave Optics)

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