Insertion effects of natural dielectric between artificial dielectrics formed by metallic sub-wavelength slit arrays
Insertion effects of natural dielectric between artificial dielectrics formed by metallic sub-wavelength slit arrays
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DOI：
10.1063/1.5043149
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发表时间：
2018-09
期刊：
影响因子：
1.6
通讯作者：
Y. Tokuda;K. Takano;K. Sakaguchi;Kosaku Kato;M. Nakajima;K. Akiyama
中科院分区：
文献类型：
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作者：
Y. Tokuda;K. Takano;K. Sakaguchi;Kosaku Kato;M. Nakajima;K. Akiyama
我们研究了当入射光波长于狭缝周期时，在金属亚波长狭缝阵列之间插入天然介质的超材料系统的光学传输特性。利用太赫兹时域光谱技术测量了光纤的透射谱，并对实验结果进行了基于时域有限差分方法的模拟分析。我们发现，谐振特性是由狭缝内外开口的两个衍射极限频率定义的，这两个频率对于插入介质是不同的。我们还通过考虑插入的中间介质的折射率，确定了偶数阶共振模特有的蓝移行为的进一步细节。此外，我们还从实验上证明了高折射率介质的插入增强了对称和反对称光学模间的频率斥力，即耦合强度。这些实验和理论结果对于理解和开发由具有固定和广泛可调折射率的介质组成的混合系统的应用是必不可少的。我们研究了当入射光波长于缝隙周期时，在金属亚波长缝隙阵列之间插入天然介质的超材料系统的光传输特性。利用太赫兹时域光谱技术测量了光纤的透射谱，并对实验结果进行了基于时域有限差分方法的模拟分析。我们发现，谐振特性是由狭缝内外开口的两个衍射极限频率定义的，这两个频率对于插入介质是不同的。我们还通过考虑插入的中间介质的折射率，确定了偶数阶共振模特有的蓝移行为的进一步细节。此外，我们还从实验上证明了高折射率介质的插入增强了防腐时的频率斥力，也就是说，提高了抗腐蚀的频率斥力。
We investigated the optical transmission properties of a metamaterial system in which a natural dielectric is inserted between metallic sub-wavelength slit arrays that behave as an artificial dielectric when the incident light wavelength is longer than the slit periodicity. Transmission spectra were measured using terahertz time-domain spectroscopy, and the experimental results were analyzed by simulations based on the finite-difference time-domain method. We revealed that the resonance characteristics are defined by the two diffraction-limit frequencies for the inner and outer openings of the slits, which are different for the insertion of the dielectric. We also determined further details on the blue-shift behavior specific to the even-order resonance modes by accounting for the refractive index of the inserted intermediate dielectric. In addition, we experimentally demonstrated that insertion of a dielectric having a high refraction index enhances the frequency repulsion at the anticrossing, i.e., the coupling strength, between the symmetric and antisymmetric optical modes. These experimental and theoretical results will be essential for understanding and developing applications for hybrid systems composed of dielectrics with both fixed and widely tunable refractive indices.We investigated the optical transmission properties of a metamaterial system in which a natural dielectric is inserted between metallic sub-wavelength slit arrays that behave as an artificial dielectric when the incident light wavelength is longer than the slit periodicity. Transmission spectra were measured using terahertz time-domain spectroscopy, and the experimental results were analyzed by simulations based on the finite-difference time-domain method. We revealed that the resonance characteristics are defined by the two diffraction-limit frequencies for the inner and outer openings of the slits, which are different for the insertion of the dielectric. We also determined further details on the blue-shift behavior specific to the even-order resonance modes by accounting for the refractive index of the inserted intermediate dielectric. In addition, we experimentally demonstrated that insertion of a dielectric having a high refraction index enhances the frequency repulsion at the anticrossing, i.e., the ...