Resonance-enhanced transmission of surface plasmon polariton wave-packets through metal-insulator-metal nanocavities
Resonance-enhanced transmission of surface plasmon polariton wave-packets through metal-insulator-metal nanocavities
复制标题
表面等离子体激元波包通过金属-绝缘体-金属纳米腔的共振增强传输
DOI：
10.1117/12.2544586
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Kubo Atsushi
中科院分区：
文献类型：
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作者：
Ichiji Naoki;Kubo Atsushi
利用数值模拟和时间分辨显微技术研究了由金属-绝缘体-金属结构组成的纳米空腔（MIM纳米空腔）与飞秒表面等离子激元（SPP）波包之间的光学相互作用。时域有限差分（FDTD）模拟表明，当纳米腔的本征频率落在SPP波的谱宽范围内时，入射波包引起腔的共振激励。spp -腔相互作用的共振效应在透射波包和反射波包的光谱中表现为强调制。由于MIM纳米腔将波包分成共振频率作为透射频率和共振频率作为反射频率，因此传输/反射分量的包络和光谱形状都发生了很大的变形。特别是当入射波的谱宽等于或小于谐振腔的谱宽时，透射波包的整体强度变化较大。利用光谱宽度与腔共振线宽相当的10fs激光脉冲进行时间分辨成像，与仿真结果吻合较好。在选择MIM纳米腔的长度使本征模式不与10fs激光的谱线重叠的情况下，透射波包的强度表现出相当大的衰减。这些特征可以解释为MIM腔的功能作为一个法布里-普氏准子。
We study optical interactions between nano-scaled cavities consist of metal-insulator-metal structures (MIM nano-cavity) with femtosecond surface plasmon polariton (SPP) wavepackets in terms of numerical simulations and time-resolved microscopy methods. Finite-difference time-domain (FDTD) simulations show that when the eigen-frequency of the nanocavity falls within the spectral width of the SPP wave, the incident wavepacket causes resonant excitations of the cavity. The resonance effect of the SPP-cavity interaction is reflected as strong modulations in the spectra of transmitted and reflected wavepackets. Because the MIM nanocavity separates the wavepacket into resonance frequencies as the transmission and others as the reflection, both the envelope and the spectral shapes of the transmitted/reflected components are largely deformed. Particularly, when the spectrum width of the incident wave was equivalent to or narrower than the resonance linewidth of the cavity, the whole intensity of the transmitted wavepacket varied largely. The time-resolved imaging by using a 10 fs laser pulse, of which spectral width is comparable to the linewidth of cavity resonance, shows reasonable agreement with the simulation. In the case the length of the MIM nano-cavity is chosen so that the eigen-modes do not have spectral overlap with that of the 10 fs laser, the intensity of the transmitted wavepackets showed a considerable attenuation. These features can be interpreted in terms of the functionality of the MIM cavity as a Fabry–Pérot etalon.