Majérus Bruno, Butet Jérémy, Bernasconi Gabriel D, Valapu Raziman Thottungal, Lobet Michaël, Henrard Luc, Martin Oliver J F
Opt Express. 2017 Oct 30;25(22):27015-27027. doi: 10.1364/OE.25.027015.
Optical second harmonic generation (SHG) from nanostructured graphene has been studied in the framework of classical electromagnetism using a surface integral equation method. Single disks and dimers are considered, demonstrating that the nonlinear conversion is enhanced when a localized surface plasmon resonance is excited at either the fundamental or second harmonic frequency. The proposed approach, beyond the electric dipole approximation used in the quantum description, reveals that SHG from graphene nanostructures with centrosymmetric shapes is possible when retardation effects and the excitation of high plasmonic modes at the second harmonic frequency are taken into account. Several SHG effects similar to those arising in metallic nanostructures, such as the silencing of the nonlinear emission and the design of double resonant nanostructures, are also reported. Finally, it is shown that the SHG from graphene disk dimers is very sensitive to a relative vertical displacement of the disks, opening new possibilities for the design of nonlinear plasmonic nanorulers.
利用表面积分方程法，在经典电磁学框架下研究了纳米结构石墨烯的光学二次谐波产生（SHG）。考虑了单盘和二聚体，结果表明，当在基频或二次谐波频率激发局域表面等离子体共振时，非线性转换会增强。所提出的方法超越了量子描述中使用的电偶极近似，揭示了在考虑延迟效应和二次谐波频率下高等离子体模式的激发时，具有中心对称形状的石墨烯纳米结构产生SHG是可能的。还报道了几种与金属纳米结构中出现的类似的SHG效应，如非线性发射的消光和双共振纳米结构的设计。最后表明，石墨烯盘二聚体的SHG对盘的相对垂直位移非常敏感，为非线性等离子体纳米尺的设计开辟了新的可能性。
