Nonlocality-driven supercontinuum white light generation in plasmonic nanostructures.
Nonlocality-driven supercontinuum white light generation in plasmonic nanostructures.
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DOI：
10.1038/ncomms11497
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发表时间：
2016-05-09
影响因子：
16.6
通讯作者：
Zayats AV
中科院分区：
文献类型：
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作者：
Krasavin AV;Ginzburg P;Wurtz GA;Zayats AV
结构化等离子体金属由于其限制和增强电磁场的能力以及强的固有非线性而被广泛用于实现纳米级的非线性功能。中心对称金属中的光学非线性主要由传导电子动力学决定，在纳米尺度下，传导电子动力学会受到非局域效应的显著影响。在这里，我们表明，非局部校正，通常是小的线性光学响应，定义等离子体纳米结构的非线性特性。使用一个完整的非微扰时域流体动力学描述的飞秒激发下的电子等离子体，我们数值研究金属阿基米德纳米螺旋的谐波产生，揭示几何和非局部效应之间的相互作用。非线性流体力学模型中的量子压力项导致分数阶非线性谐波的出现，从而产生宽带相干白光。所描述的效果提出了一类新的非线性现象，在金属纳米结构确定的非局域性的电子响应。 金属的非线性响应的理论描述是复杂的，由于其复杂的电子行为。在这里，Krasavin等人使用与麦克斯韦方程耦合的流体动力学模型，并演示了从金属阿基米德螺旋形状产生的高次谐波和超连续谱
Structured plasmonic metals are widely employed for achieving nonlinear functionalities at the nanoscale due to their ability to confine and enhance electromagnetic fields and strong, inherent nonlinearity. Optical nonlinearities in centrosymmetric metals are dominated by conduction electron dynamics, which at the nanoscale can be significantly affected by the nonlocal effects. Here we show that nonlocal corrections, being usually small in the linear optical response, define nonlinear properties of plasmonic nanostructures. Using a full non-perturbative time-domain hydrodynamic description of electron plasma under femtosecond excitation, we numerically investigate harmonic generation in metallic Archimedean nanospirals, revealing the interplay between geometric and nonlocal effects. The quantum pressure term in the nonlinear hydrodynamic model results in the emergence of fractional nonlinear harmonics leading to broadband coherent white-light generation. The described effects present a novel class of nonlinear phenomena in metallic nanostructures determined by nonlocality of the electron response. A theoretical description of the nonlinear response of metals is complicated due to their complex electron behavior. Here, Krasavin et al. use a hydrodynamic model coupled with Maxwell's equations and demonstrate higher harmonics and supercontinuum generation from metal Archimedean spiral shapes