Nonlinear optics in complex, chiral, and 3D plasmonic nanostructures

在这个提议中，我们将研究复杂等离子体纳米结构暴露于超快激光脉冲时的非线性光学响应。我们的目标是了解第二和第三谐波产生的非线性光学张量在从头算的方式。特别是，我们将利用复杂的等离子体结构，如混合纳米天线，2-和3-维复杂的低聚物，和3-维手性等离子体超材料作为非线性介质。此外，我们将利用混合结构，其中复杂的等离子体纳米结构与本身表现出Chi（2）或Chi（3）非线性的电介质纳米结构组合。 我们将利用时间积分和时间分辨光谱，我们将研究不同波长和偏振的影响，以及它们的角度依赖性。 我们的工作不仅应该导致对非线性光学机制的基本理解，这些机制可以通过定制适当的等离子体纳米结构来增强，而且还可以用于新的应用，例如等离子体增强的中红外和太赫兹产生以及非线性等离子体传感。

In this proposal, we are going to study the nonlinear optical response of complex plasmonic nanostructures upon exposure to ultrafast laser pulses. Our goal is to understand the nonlinear optical tensor for second- and third-harmonic generation in an ab-initio fashion. In particular, we are going to utilize complex plasmonic structures such as hybrid nanoantennas, 2- and 3-dimensional complex oligomers, and 3-dimensional chiral plasmonic metamaterials as nonlinear media. Furthermore, we will utilize hybrid structures, where the complex plasmonic nanostructures are being combined with dielectric nanostructures which exhibit Chi(2) or Chi(3) nonlinearities themselves. We are going to utilize time-integrated as well as time-resolved spectroscopy, and we will study the effects for different wavelengths and polarizations, as well as their angle dependence. Our work should lead not only to a fundamental understanding of the nonlinear optical mechanisms that can be enhanced largely by tailoring appropriate plasmonic nanostructures, but also to novel applications, such as plasmonically enhanced mid-IR and THz generation as well as nonlinear plasmonic sensing.