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 共查询到20条相似文献,搜索用时 7 毫秒
1.
We present a computational study of the plasmonic response of a split nanoring dimer resonator which supports multiple plasmonic Fano-like resonances that arises by the coupling and interference of the dimer plasmon modes. For the generation of Fano resonances with large modulation depths, numerous configurations of the dimer resonator are analyzed which are observed to be highly dependent on the polarization of incident light. Moreover, the influence of dimension of the split nanoring structure on the spectral positions and intensities of the higher order Fano resonances are also investigated, and it is found that the asymmetric Fano line shapes can be flexibly tuned in the spectrum by varying various geometrical parameters. Such Fano resonators are also discovered to offer high values of figure of merit and contrast ratio due to which they are suitable for high-performance biological sensors.  相似文献   

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3.
In this work, we conceive and demonstrate the magneto-electric double Fano resonances of a hetero-cavity composed of Si disk and Au split ring, where Si disk can provide additional magnetic responses besides electric responses. The interference between electric and magnetic responses in proposed hetero-cavity gives rise to magneto-electric double Fano resonances with magnetic and electric near-field enhancements. Dipole radiative enhancement is used to analyze magnetic and electric responses of hetero-cavity and the spectral features of hetero-cavity can be used to quantitatively characterize by coupled oscillator model. And the spectral tunability of magneto-electric double Fano resonances is investigated, highlighting a potential for applications in low-loss sensing and nanophotonic devices.  相似文献   

4.
Zhang  Xingfang  Yan  Xin  Liu  Fengshou  Liang  Lanju 《Plasmonics (Norwell, Mass.)》2021,16(4):1041-1048
Plasmonics - Split theta-shaped nanocavities composed of an elliptical disk embedded in a nonconcentric split ring are theoretically investigated by the finite-difference time-domain method....  相似文献   

5.
Cui  Jian  Ji  Boyu  Song  Xiaowei  Lin  Jingquan 《Plasmonics (Norwell, Mass.)》2019,14(1):41-52
Plasmonics - Generation of multiple Fano resonances are theoretically investigated in asymmetry ring-disk and asymmetry split-ring-disk. The effects of structural parameter on multiple Fano...  相似文献   

6.
Wang  Jin  Yang  Guofeng  Ye  Xuanchao  Zhang  Qing  Gao  Shumei  Chen  Guoqing 《Plasmonics (Norwell, Mass.)》2017,12(5):1641-1647
Plasmonics - We theoretically explore the appearances and characteristics of Fano resonances in novel-designed nanobelt cluster, which shows strong modulation depths, and the Fano dips can be...  相似文献   

7.
We proposed a plasmonic nanosensor with an ultra-high sensitivity based on groove and ring resonator. Simulation results show that these sharp Fano profiles originate from the interference between the groove and ring resonator. The profile can be easily tuned by changing the parameters of the structure. Moreover, we introduce a new way to achieve multiple Fano resonances through independent processes by adding a side-coupled stub cavity, and the Fano resonances can be tuned independently. These characteristics offer flexibility in the design of the devices. This nanosensor yields an ultra-high sensitivity of ~2000 nm/RIU, which is rarely seen in the previous report. Our structures may have potential applications for nanosensors, slow light, and nonlinear devices in highly integrated circuits.  相似文献   

8.
Zhou  Hang  Gao  Dongliang  Gao  Lei 《Plasmonics (Norwell, Mass.)》2018,13(2):623-630
Plasmonics - We study the multipolar surface plasmon modes and its link to Fano resonances in bimetallic nanoparticles. General expressions for the multipolar surface plasmon frequencies and...  相似文献   

9.
Zhou  Chen  Huo  Yiping  Guo  Yiyuan  Niu  Qiqiang 《Plasmonics (Norwell, Mass.)》2021,16(5):1735-1743
Plasmonics - A metal-insulator-metal (MIM) waveguide consisting of two stub resonators and a ring resonator is proposed, which can be used as refractive index sensor and stop-band filter at the...  相似文献   

10.
We present high-quality (high-Q) Fano resonances in all-dielectric metasurfaces consisting of a periodic array of air holes on silicon (Si) film, deposited on the top of quartz substrate. With the control of the radius difference Δr and center distance Δd between the air holes, two asymmetric all-dielectric metasurfaces are proposed to achieve extremely high-Q Fano resonances. Numerical method with finite difference time domain and equivalent circuit model is employed to analyse the excitation mechanism of the sharp Fano resonances. It is shown that the high-Q Fano resonances come from the interference of two Fabry-Perot resonances, resulting in an extremely narrow window. Moreover, we also demonstrate that the high-Q Fano resonances can also be realized as electromagnetic wave is obliquely incident on the symmetric all-dielectric metasurface. Finally, we show the high-Q Fano resonances caused by asymmetric configurations can coexist with the Fano resonances in the symmetric configuration induced by oblique incidence. As a result, a tri-band Fano resonance is obtained. It is expected that our results will provide important mechanisms for tuning and switching a wide variety of optical devices such as angular sensors, filters, switches, and modulators.  相似文献   

11.
Zheng  Gaige  Zhang  Haojing  Bu  Lingbing  Gao  Haiyang  Xu  Linhua  Liu  Yuzhu 《Plasmonics (Norwell, Mass.)》2018,13(1):215-220

A planar silicon carbide/dielectric multilayer structure is investigated in Otto geometry, where surface phonon polaritons and planar waveguide mode can be coupled to realize Fano resonances under transverse magnetic polarization. The resonance coupling is analytically demonstrated using the coupled harmonic oscillator model and numerically presented through rigorous coupled-wave analysis calculations, which shows that the coupling strength between different resonances and the resonant wavelength matching condition plays an important role in the bandwidth and position of the Fano resonance (FR); the magnetic field distribution was also shown to explain the origin of FRs qualitatively.

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12.
We present a computational study of the plasmonic response of a gold–silica–gold multilayered nanostructure based on truncated nanocones. Symmetry breaking is introduced by rotating the nanostructure and by offsetting the layers. Nanocones with coaxial multilayers show dipole–dipole Fano resonances with resonance frequencies depending on the polarization of the incident light, which can be changed by rotating the nanostructure. By breaking the axial symmetry, plasmonic modes of distinct angular momenta are strongly mixed, which provide a set of unique and higher order tunable Fano resonances. The plasmonic response of the multilayered nanocones is compared to that of multishell nanostructures with the same volume and the former are discovered to render visible high-order dark modes and to provide sharp tunable Fano resonances. In particular, higher order tunable Fano resonances arising in non-coaxial multilayer nanocones can vary the plasmon lines at various spectral regions simultaneously, which makes these nanostructures greatly suitable for plasmon line shaping both in the extinction and near field spectra.  相似文献   

13.
Plasmonic Fano resonances arise in symmetric single-layer conical nanoshells, which can be switched on and off by changing the polarization of the incident electric field. By breaking the symmetry, higher-order dark hybridized modes emerge in the spectrum, which couple to the superradiant bright mode and induce higher-order plasmonic Fano resonances. From a comparison with spherical nanostructures, it comes out that single-layer conical nanoshells are found to be highly capable in the generation of higher-order Fano resonances with larger modulation depths in the optical spectra. Such nanostructures are also found to offer high values of figure of merit and contrast ratio due to which they are highly suitable for biological sensors.  相似文献   

14.
Wu  Tengfei  Yang  Shaobo  Tan  Wenbin  Li  Xingfei 《Plasmonics (Norwell, Mass.)》2016,11(5):1351-1359
Plasmonics - We present a numerical study of the plasmonic properties of Au core-semishell. Symmetry breaking in semishell results in a dipole–quadrupole Fano resonance without the offset of...  相似文献   

15.
Metallic nanostructures that support multipolar Fano resonances have drawn much attention in recent years. Such structures are applicable especially to enhanced nonlinear optics, where two resonance wavelengths need to be modulated simultaneously. However, how to tune multipolar Fano resonances independently remains a challenge. In the paper, the plasmonic nanostructure consisting of two ring/disk cavities (RDCs) is investigated using the finite element method. The dark multipolar modes of each RDC are excited, and sharp multipolar Fano resonances are induced. The multipolar modes supported by different RDCs can be tuned independently by changing the sizes. The line-widths of such Fano resonances nearly keep below 0.05 eV, and the contrast ratio (CR) of the two quadrupolar Fano dips mostly maintain above 50 %. In addition, the exciting bonding modes of different RDCs make the selective storage of resonance energy available. Such plasmonic nanostructures may find applications in enhanced nonlinear optics or nano-optical elements.  相似文献   

16.
Wang  Wudeng  Wang  Yongliang  Shi  Ying  Liu  Yujie 《Plasmonics (Norwell, Mass.)》2017,12(5):1537-1543
Plasmonics - Compared to metallic nanostructures employed in plasmonics, dielectric materials with high refractive index can directly engineer magnetic responses in addition to the electric...  相似文献   

17.
Chen  Ying  Zhang  Min  Cao  Jinggang  Xiao  Chunyan  Zhu  Qiguang 《Plasmonics (Norwell, Mass.)》2021,16(5):1719-1728

A structure of double-baffle metal-dielectric-metal (MDM) waveguide coupled cascaded square cavity is designed based on the transmission characteristics of the surface plasmon polaritons. Combined with coupled mode theory (CMT), the mechanism of multiple Fano resonances generated by this structure is analyzed qualitatively. The wide-band spectrum mode generated by the F-P resonant cavity and the four narrow-band spectrum modes produced by the cascaded square resonant cavities interfere with each other. Moreover, an new scheme of introducing a semiconductor material InGaAsP into this structure is designed for improving the transmittance of the Fano peaks. Analyze the influence of refractive indexes of the test objects on sensing performance by finite element method (FEM) quantitatively, which shows the improved structure can achieve the independent tuning of multiple Fano resonances. Combining with 96-well microplate technology, the structure can achieve the detection of multiple different samples with high-performance simultaneously. It is believed that the proposed structure has a strong reference significance for the design of optical micro-nanostructures for high throughput detection.

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18.
Huang  Yu  Ma  Lingwei  Hou  Mengjing  Zhang  Zhengjun 《Plasmonics (Norwell, Mass.)》2016,11(5):1377-1383
Plasmonics - We have demonstrated directly that the physical origin of Fano resonances in two-dimensional (2D) plasmonic crystals (PCs) is a wave-interference phenomenon. This is achieved by...  相似文献   

19.
Fano resonances are numerically predicted in an ultracompact plasmonic structure, comprising a metal-isolator-metal (MIM) waveguide side-coupled with two identical stub resonators. This phenomenon can be well explained by the analytic model and the relative phase analysis based on the scattering matrix theory. In sensing applications, the sensitivity of the proposed structure is about 1.1?×?103 nm/RIU and its figure of merit is as high as 2?×?105 at λ?=?980 nm, which is due to the sharp asymmetric Fano line-shape with an ultra-low transmittance at this wavelength. This plasmonic structure with such high figure of merits and footprints of only about 0.2 μm2 may find important applications in the on-chip nano-sensors.  相似文献   

20.
A simple T-shaped plasmonic nanostructure composed of two perpendicular coupled nanorods is proposed to produce strong Fano resonances. By the near-field coupling between the “bright” dipole and “dark” quadrupole plasmons of the nanorods, a deep Fano dip is formed in the extinction spectrum, which can be well fitted by the Fano interference model. The effects of the geometry parameters including nanorod length, coupling gap size, and coupling location to the Fano resonances are analyzed in detail, and a very high refractive index sensitivity is achieved by the Fano resonance. Also by adjusting the incident polarization direction, double Fano resonances can be formed by the interferences of the dipole, quadrupole, and hexapole plasmons. The proposed nanorod dimer structure is agile, and a trimer which supports double Fano resonances can be easily formed by introducing a third perpendicular coupled nanorod. The proposed T-shaped nanorod dimer structure may have applications in the fields of biological sensing and plasmon-induced transparency.  相似文献   

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