Plasmonic TM-like cavity modes and the hybridization in multilayer metal-dielectric nanoantenna

Zhang, X. M.; Xiao, Jun Jun; Zhang, Q.; Li, L. M.; Yao, Yu

doi:10.1364/oe.23.016122

Cited by 14 publications

(18 citation statements)

References 35 publications

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“…35 A figure of merit to describe the enhancement is the radiative decay rate enhancement, Γ rad = P rad / P 0 , where P rad is the radiated power flowing through a closed surface surrounding both the dipole source and the antenna and P 0 is the radiated power of the dipole source in free space. 30 Figure 2a shows P rad spectra for the nanoantenna. To justify the calculated results by the FEM, we have superimposed the results of P rad obtained by the discrete dipole approximation (DDA).…”

Section: Resultsmentioning

confidence: 99%

Dual-Band Unidirectional Emission in a Multilayered Metal–Dielectric Nanoantenna

et al. 2017

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Controlling the emission efficiency, direction, and polarization of optical sources with nanoantennas is of crucial importance in many nanophotonic applications. In this article, we design a subwavelength multilayer metal–dielectric nanoantenna consisting of three identical gold strips that are separated by two dielectric spacers. It is shown that a local dipole source can efficiently excite several hybridized plasmonic modes in the nanoantenna, including one electric dipole (ED) and two magnetic dipole (MD) resonances. The coherent interplay between the ED and MDs leads to unidirectional emissions in opposite directions at different wavelengths. The relative phase difference between these resonant modes determines the exact emission direction. Additionally, with a proper spacer thickness and filling medium, it is possible to control the spectral positions of the forward and backward unidirectional emissions and to exchange the wavelengths for two unidirectional emissions. An analytical dipole model is established, which yields comparable results to those from the full-wave simulation. Furthermore, we show that the wavelength of the peak forward-to-backward unidirectionality is essentially determined by the MD and is approximately predictable by the plasmonic wave dispersion in the corresponding two-dimensional multilayer structure. Our results may be useful to design dual-band unidirectional optical nanoantennas.

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Section: Resultsmentioning

confidence: 99%

Dual-Band Unidirectional Emission in a Multilayered Metal–Dielectric Nanoantenna

et al. 2017

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“…42,45 The principle of this method is based on the fact that the resonance frequency of CM nm versus ' / mn eff R  shall approximately fall on the dispersion of the gap SPPs, where ' nm  is the n -th zero point of the derivative of m -th Bessel function. 42,45,63 Therefore the resonance frequency of the In more details, Figure 5a shows that as the loaded material dielectric function increases from 1 load   to 21, both the AM band and the CM bands redshift. However, the AM band is less sensitive than the CM bands with respect to the load  variation.…”

Section: Resultsmentioning

confidence: 99%

“…In this study, () gsp k  is obtained from the divergence of the reflection coefficient calculated by the transfer matrix method of a 2D metal-dielectric-metal three layer system. 42,63 The black dashed lines in Figure 5…”

Section: After Obtaining the Dispersion Relation Of The Gap Sppsmentioning

confidence: 99%

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Coexistence of Scattering Enhancement and Suppression by Plasmonic Cavity Modes in Loaded Dimer Gap-Antennas

Zhang

Xiao

et al. 2015

Sci Rep

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Plasmonic nanoantenna is of promising applications in optical sensing and detection, enhancement of optical nonlinear effect, surface optical spectroscopy, photoemission, etc. Here we show that in a carefully-designed dimer gap-antenna made by two metallic nanorods, the longitudinal plasmon antenna mode (AM) of bonding dipoles can compete with the transverse plasmonic cavity modes (CMs), yielding dramatically enhanced or suppressed scattering efficiency, depending on the CMs symmetry characteristics. More specifically, it is demonstrated that an appropriately loaded gap layer enables substantial excitation of toroidal moment and its strong interaction with the AM dipole moment, resulting in Fano- or electromagnetically induced transparency (EIT)-like profile in the scattering spectrum. However, for CMs with nonzero azimuthal number, the spectrum features a cumulative signature of the respective AM and CM resonances. We supply both detailed near-field and far-field analysis, showing that the modal overlap and phase relationship between the fundamental moments of different order play a crucial role. Finally, we show that the resonance bands of the AM and CMs can be tuned by adjusting the geometry parameters and the permittivity of the load. Our results may be useful in plasmonic cloaking, spin-polarized directional light emission, ultra-sensitive optical sensing, and plasmon-mediated photoluminescence.

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“…Surface plasmon polaritons (SPPs) refer to collective oscillations of conductive electrons at metal and dielectric interface [1]. With metallic nanostructures at the interface, these excitations couple strongly with light, giving rise to large interaction cross-sections, and enhanced near-fields [2,3].…”

Section: Introductionmentioning

confidence: 99%

Tunable Unidirectivity of Metal-Dielectric-Metal Plasmonic Nanoantennas With PT-Symmetric Potentials

Zhang

Cheng

et al. 2019

Front. Phys.

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Parity-time (PT) symmetric photonic systems have attracted much attention due to their intriguing properties and asymmetric behaviors. In this paper, we propose a plasmonic nanoantenna with PT-symmetric potential for unidirectional scattering functionality. The studied plasmonic nanoantenna is comprised of three metallic layers separated by two dielectric layers. Such kind of system, with the same coefficient κ of loss and gain in each of the two dielectric layers, holds the characteristic of PT symmetry. We show that the unidirectional scattering is obtained for the passive structure (i.e., κ = 0), and the switching between forward and backward directionality can be achieved with a single structure by changing the excitation wavelength, when the induced electric dipole (ED) and magnetic dipole (MD) modes satisfy the first or second Kerker conditions, respectively. In addition, we find that the forward-to-backward ratio spectra can be strongly affected by the non-Hermiticity parameter κ. In particular, it is possible to reverse the radiation direction at the same wavelength in a wide spectra band by adjusting κ. Moreover, putting the nanoantennas in an array of transverse configuration can efficiently narrow the main lobe angular beam width to be <6 •. These results contribute to the basic understanding of the optical properties of active-passive finite nanostructures with potential applications, and provide new ideas for the design of novel nanostructures displaying asymmetric and tunable responses.

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Plasmonic TM-like cavity modes and the hybridization in multilayer metal-dielectric nanoantenna

Cited by 14 publications

References 35 publications

Dual-Band Unidirectional Emission in a Multilayered Metal–Dielectric Nanoantenna

Dual-Band Unidirectional Emission in a Multilayered Metal–Dielectric Nanoantenna

Coexistence of Scattering Enhancement and Suppression by Plasmonic Cavity Modes in Loaded Dimer Gap-Antennas

Tunable Unidirectivity of Metal-Dielectric-Metal Plasmonic Nanoantennas With PT-Symmetric Potentials

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