Nonlinear Photonics with Metallic Nanostructures on Top of Dielectrics and Waveguides

在本项目中，我们将研究纳米介观金属纳米结构和强相关材料的光学性质。我们想研究分离的和强耦合的纳米粒子。利用连续波和超快（飞秒和皮秒）光谱学对其光学特性进行了研究。金属纳米颗粒正在成为纳米光学的重要组成部分。然而，为了能够在介观尺度上定位光，有必要了解光与这种纳米结构耦合的确切机制，以及它的能量如何转移到电子激发（粒子等离子激元）中。此外，有必要了解这些激发如何转移到邻近的粒子并辐射回空间。当将粒子排列成规则的金属纳米结构时，有必要了解这种超材料的线性和非线性光学性质。我们的项目旨在阐明金属纳米结构中光-物质耦合的时间动力学和控制。强相关材料被认为有潜力成为最快的光开关。然而，到目前为止，只有少数实验证明了这些系统中理论上计算出的准粒子的存在，如磁振子和自旋子。人们对这些准粒子的超快时间动力学（寿命和消相）几乎一无所知。我们的项目旨在研究这些基本过程，使用最先进和新颖的超快方法。

In this project we are going to investigate the optical properties of nanoscale mesoscopic metallic nanostructures and of strongly correlated materials. We want to study both isolated and strongly coupled nanoparticles. The optical properties are being investigated by continuous wave and by ultrafast (femtosecond and picosecond) spectroscopy. Metallic nanoparticles are becoming an important building block in nano-optics. However, in order to be able to localize light on a mesoscopic scale, it will be necessary to understand the exact mechanism how light couples to such nanostructures and how its energy is being transferred into electronic excitations (particle plasmons). Furthermore, it is necessary to unterstand how these excitations can transfer to neighboring particles and reradiate back into space. When arranging the particles into a regular metallic nano-structure, it will be necessary to understand the linear and nonlinear optical properties of such metamaterials. Our project aims to clarify the temporal dynamics and the control of light-matter coupling in metallic nanostructures. Strongly correlated materials are believed to have the potential for the fastest optical switches available. However, only a few experiments have so far proven the existence of theoretically calculated quasiparticles in these systems, such as magnons and spinons. Nearly nothing is known about the ultrafast temporal dynamics (lifetime and dephasing) of these quasiparticles. Our project aims to investigate these elementary processes, using state-of-the art and novel ultrafast methods.