Key Laboratory of Artificial Micro- and Nano-structures of the Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan, 430072, P.R. China.
The Institute for Advanced Studies, Wuhan University, Wuhan, 430072, P.R. China.
Sci Rep. 2017 Aug 29;7(1):9776. doi: 10.1038/s41598-017-10243-y.
We theoretically study the gain-assisted double plasmonic resonances to enhance second harmonic generation (SHG) in a centrosymmetric multilayered silver-dielectric-gold-dielectric (SDGD) nanostructure. Introducing gain media into the dielectric layers can not only compensate the dissipation and lead to giant amplification of surface plasmons (SPs), but also excite local quadrupolar plasmon which can boost SHG by mode matching. Specifically, as the quadrupolar mode dominates SHG in our nanostructure, under the mode matching condition, the intensity of second harmonic near-field can be enhanced by 4.43 × 10 and 1.21 × 10 times when the super-resonance is matched only at the second harmonic (SH) frequency or fundamental frequency, respectively. Moreover, the intensity of SHG near-field is enhanced by as high as 6.55 × 10 times when the nanostructure is tuned to double super-resonances at both fundamental and SH frequencies. The findings in this work have potential applications in the design of nanosensors and nanolasers.
我们从理论上研究了增益辅助的双等离子体共振，以增强中心对称多层银-介电-金-介电（SDGD）纳米结构中的二次谐波产生（SHG）。在介电层中引入增益介质不仅可以补偿损耗并导致表面等离子体（SP）的巨大放大，还可以激发出局域四极等离子体，通过模式匹配来增强 SHG。具体来说，由于我们的纳米结构中的四极模式主导 SHG，在模式匹配条件下，当仅在二次谐波（SH）频率或基频处匹配超共振时，二次谐波近场的强度可以分别增强 4.43×10 和 1.21×10 倍。此外，当纳米结构调谐到基频和 SH 频率的双重超共振时，SHG 近场的强度可高达增强 6.55×10 倍。这项工作的发现具有在纳米传感器和纳米激光器设计中的潜在应用。
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