Coupling of Planar Waveguide Modes in All-Dielectric Multilayer Structures: Monitoring the Dependence of Local Electric Fields on the Coupling Strength
Coupling of Planar Waveguide Modes in All-Dielectric Multilayer Structures: Monitoring the Dependence of Local Electric Fields on the Coupling Strength
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全电介质多层结构中平面波导模式的耦合：监测局部电场对耦合强度的依赖性
DOI：
10.1103/physrevapplied.16.064065
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发表时间：
2021
影响因子：
4.6
通讯作者：
Hayashi Shinji
中科院分区：
文献类型：
--
作者：
Motokura Kengo;Fujii Minoru;Nesterenko Dmitry V.;Sekkat Zouheir;Hayashi Shinji
除了少数应用复杂技术的情况外，很难在实验上观察到与纳米结构积木支撑的电磁模式的激发相关的局部电场或近场。虽然阐明局部电场或近场的行为对于开发纳米结构的潜在应用非常有用，但在许多情况下，它们的行为只能通过基于电磁理论的模拟来推测。在这里，我们发展了一种简单的技术，它允许我们实验研究在全介质多层结构中相互作用的两个平面波导层内的局部电场的平均行为。这项研究是通过在两个波导层中掺杂两个不同的荧光团来实现的。在两个不同波长探测到的荧光强度使我们能够分别研究每个波导层内的局部电场行为。通过在衰减全反射几何结构中激发样品，测量了两个不同系列的多层膜样品的角度扫描荧光激发光谱。观察到的谱线形状与根据电磁理论计算的理论线形吻合很好，证实了实验的荧光激发光谱很好地反映了局域电场的平均行为。应用所发展的方法，系统地研究了波导层内局域电场随两波导模之间耦合强度的变化而产生的变化。在一系列样品中，随着耦合强度的增加，局部电场的行为从Fano共振行为逐渐转变为双峰行为。在另一系列样品中，耦合强度变化很大，在强耦合区可以清楚地观察到耦合模的形成。通过基于耦合振子模型的简单解析计算，可以很好地再现所观察到的局域电场变化。该模型有助于对电磁场计算所不能得到的波导模的耦合有更深入的物理了解。
Except for a few cases to which sophisticated techniques are applicable, it is difficult to observe experimentally local electric fields or near fields associated with excitation of electromagnetic modes supported by building blocks of nanostructures. Although elucidating the behavior of the local electric fields or near fields is very useful to develop potential applications of the nanostructures, in many cases, their behaviors have been only speculated from simulations based on the electromagnetic theory. Here, we develop a simple technique that allows us to study experimentally the average behavior of the local electric fields inside two planar waveguide layers interacting with each other in all-dielectric multilayer structures. The study is made possible by doping the two waveguide layers with two different fluorophores. Fluorescence intensities detected at two different wavelengths allow us to study separately the behaviors of the local electric fields inside each waveguide layer. Angle-scan fluorescence excitation spectra are measured for two different series of multilayer samples by exciting the samples in an attenuated total reflection geometry. The line shapes observed are in good agreement with theoretical ones calculated based on the electromagnetic theory, confirming that the experimental fluorescence excitation spectra reflect well the average behaviors of the local electric fields. Applying the developed technique, we investigate systematically the changes in the local electric fields inside the waveguide layers caused by the change in the strength of coupling between the two waveguide modes. In one series of the samples, a gradual transition in the behavior of the local electric fields, from a Fano-resonant behavior to a double-peak behavior, is demonstrated with increasing the coupling strength. In another series of the samples, the coupling strength is widely changed and the formation of the coupled modes in a strong coupling regime is clearly observed. The observed changes in the local electric fields can be reproduced very well by simple analytical calculations based on a coupled oscillator model. The model is helpful to gain physical insights into the coupling of the waveguide modes, which cannot be obtained by the electromagnetic calculations.
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影响因子：
3.2
作者：
Ken Motokura;Byungjun Kang;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi
通讯作者：
Ken Motokura;Byungjun Kang;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi
金属-绝缘体-金属结构中表面等离子体极化子色散的反交叉行为
影响因子：
3
作者：
S. Refki;S. Hayashi;A. Rahmouni;D. Nesterenko;Z. Sekkat
通讯作者：
Z. Sekkat
影响因子：
3.2
作者：
Ken Motokura;Byungjun Kang;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi
通讯作者：
Ken Motokura;Byungjun Kang;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi
影响因子：
4.6
作者：
Hayashi S;Nesterenko DV;Rahmouni A;Ishitobi H;Inouye Y;Kawata S;Sekkat Z
通讯作者：
Sekkat Z
影响因子：
2.1
作者：
Byungjun Kang;Ken Motokura;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi
通讯作者：
Byungjun Kang;Ken Motokura;M. Fujii;D. Nesterenko;Z. Sekkat;S. Hayashi