Plasmon-Amplified Third Harmonic Generation in Metal/Dielectric Resonators
Plasmon-Amplified Third Harmonic Generation in Metal/Dielectric Resonators
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DOI：
10.1007/s11468-021-01444-3
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发表时间：
2021-04-29
期刊：
影响因子：
3
通讯作者：
Merdji，Hamed
中科院分区：
文献类型：
--
作者：
Nicolas，Rana;Shi，Liping;Merdji，Hamed
在纳米尺度上增强超快非线性过程有可能创造出可用于许多应用的高能光子或粒子的新型纳米源，特别是用于嵌入式诊断。在这项工作中，我们研究了近太瓦强度范围内金属-电介质-金属（MDM）纳米谐振器的三次谐波（THG）等离子体放大。在我们的几何结构中，法布里-珀罗等离子体共振器达到了高的局部增强的激光电场在一个大体积的SiO2介电膜。与之前的等离子体几何结构相比，THG信号被放大了一个以上的数量级，效率更高。相对于基频激光的偏振依赖性允许纳米结构中的THG增强的ON/OFF开关，这是THG放大的等离子体起源的强签名。此外，色散扫描表明，三次谐波谱相对于其线性消光谱的峰值发生了强烈的红移。使用非线性非谐模型，我们确认三次谐波行为主要来自二氧化硅层。
Enhancing ultrafast nonlinear processes at a nanometer scale has the potential of creating novel nano-sources of energetic photons or particles useful for many applications, especially for embedded diagnostics. In this work, we investigate the plasmonic amplification of the third harmonic generation (THG) from a metal-dielectric-metal (MDM) nano-resonator in the near-terawatt intensity regime. In our geometry, the Fabry-Pérot plasmonic resonator reaches a high local enhancement of the laser electric field over a large volume of a SiO2dielectric film. The THG signal is amplified by more than one order of magnitude, with a higher efficiency compared to previous plasmonic geometries. The polarization dependence with respect to the fundamental laser allows an ON/OFF switch of the THG enhancement in the nanostructures which is a strong signature of the plasmonic origin of the THG amplification. Furthermore, the dispersion scan shows that the third harmonic spectrum is strongly redshifted with respect to the peak of its linear extinction spectrum. Using the nonlinear anharmonic model, we confirm that the third harmonic behavior dominantly arises from the silica layer.