chiralFEBID - Direct writing of chiral and nonlinear plasmonic devices

小型化的进步是信息技术技术创新的巨大推动力，渗透到所有经济部门。未来的IT系统将依赖于光子，而不是电子，后者触发了对纳米级光学设备的需求。等离子体纳米结构由于其最小几何特征不受衍射极限的限制而成为一种很有前途的方法。本项目主要研究基于等离子体纳米结构的三维纳米器件的设计、制造和测试。所提出的器件是一种手性圆偏振变换器和一种手性全光变换器，通过二次和三次谐波的产生将通信光降阶到芯片上的可见光。偏振敏感波导将用于从近场到远场的输入和输出耦合。设想的器件原型的占地面积将小于1 μm^2，这是器件小型化的关键一步。器件制造需要将完全的几何形状控制与所需的材料特性相结合。在这方面，用电子直接写入是最佳选择。虽然聚焦的电子占最小的结构特征，但直接写入提供了在一个步骤中访问三个维度。结合基于离子束的图案化可以在一个真空室内制造复杂的器件。由于等离子体系统需要具有较低损耗的金属光学响应，因此沉积和图案化材料在可见光范围内的光学响应将得到优化。材料和器件将用各种光谱技术进行表征。数值模拟和解析计算构成了实验的主干。总之，该项目将为等离子体器件的制造建立一条新的途径，并在纳米尺度上对光-物质相互作用有更深入的了解。

Progress in miniaturisation constitutes an enormous impetus for technical innovations in information technology, permeating all economic sectors. Future IT systems will rely on photons instead of electrons what triggers the need for nanoscale optical devices. Plasmonic nanostructures constitute a promising approach since their minimum geometric features are not restricted by the diffraction limit. This project will focus on designing, fabricating and testing of threedimensional nano-devices based on plasmonic nanostructures. The proposed devices are a chiral circular polarization converter and a chiral all-optical converter downscaling telecom light to visible light on chip by second and third harmonic generation. Polarisation sensitive waveguides will serve for in- and out-coupling from near to far-field. The envisaged footprint of the device prototypes will be smaller than 1 μm^2 constituting a crucial step towards device miniaturisation. The device fabrication requires the combination of full geometric shape control with desired material properties. In this regard direct writing with electrons is the optimum choice. While the focused electrons account for minimum structural features, the direct writing provides access to three dimensions in a single step. In combination with ionbeam based pattering complex devices can be fabricated within one vacuum chamber. Since plasmonic systems require a metallic optical response with preferably low losses, deposited and patterned materials will be optimized concerning their optical response in the visible range. Materials and devices will be characterized with various spectroscopic techniques. Numerical simulations and analytical calculations constitue the backbone of the experiments. In summary, the proposed project will establish a novel route for plasmonic device fabrication and lead to a deeper understanding of light-matter interaction at the nanoscale.