Small-Molecule Vapor-Deposited Materials for Integrated Nonlinear Optics

非技术描述：非线性光学材料使多个光子之间的相互作用，允许光信号控制其他光信号。这样的能力对于光学计算和光学通信网络的持续发展是非常重要的，例如今天将一切从电视频道传输到互联网的通信网络。该研究项目旨在研究和开发一种新的基本范例，该范例包括使用小有机分子构建高质量的“塑料”非线性光学材料，然后可以与当前和未来的技术一起使用，以超快的速度提供重要的新型全光数据处理能力。该研究的跨学科性质及其垂直整合方法（从分子到材料再到设备）为本科生和研究生的教育提供了多样化的训练基础，他们学习使用现代激光系统并控制（波长和时间）短光脉冲，同时接触化学和工程。技术描述：该项目旨在推进对基本非线性光学性质的理解，以及它们如何从分子转化为固态，并通过气相沉积优化分子形成具有高光学质量的致密超分子组件来创建柔性有机非线性光学材料。该研究主要集中在小分子上，其中供体-受体取代导致较低的激发态能量和较高的三阶极化率，并利用在单组分组件中获得的高分子密度，在最终大块材料中获得非谐振三阶非线性，其至少比硅玻璃大三个数量级。利用一系列非线性激光光谱技术和薄膜表征方法研究了分子的性质、蒸发物质及其相互关系。优化的分子设计导致蒸发材料具有高的玻璃状光学质量，可以与现有的集成光学技术（如硅光子学）相结合，为全光开关等应用添加有源元件。

Non-technical Description: Nonlinear optical materials enable the interaction between multiple photons, allowing light signals to control other light signals. Such capabilities are important for continuous developments in optical computing and in optical telecommunication networks such as those that today transmit everything from TV channels to the Internet. This research project aims at studying and developing a new fundamental paradigm that consists in using small organic molecules to build high-quality "plastic" nonlinear optical materials that can then be used with current and future technologies to provide important new all-optical data-processing capabilities at ultrafast speeds. The interdisciplinary nature of the research and its vertically integrated approach (from molecules to materials to devices) provide a varied training ground for the education of undergraduate and graduate students, who learn to use modern laser systems and to control (in wavelength and in time) short optical pulses, while at the same time being exposed to chemistry on one side and engineering on the other.Technical Description: The project aims at advancing the understanding of fundamental nonlinear optical properties and how they translate from molecules to the solid-state, and at creating flexible organic nonlinear optical materials by vapor deposition of optimized molecules into dense supramolecular assemblies with a high optical quality. The research focuses on small molecules where donor-acceptor substitution leads to lower excited state energies and higher third-order polarizabilities, and it exploits the high molecular densities achieved in single-component assemblies to obtain off-resonant third-order nonlinearities in the final bulk materials that are at least three orders of magnitude larger than silica glass. The properties of the molecules, the resulting evaporated materials, and their relationships are studied with a range of nonlinear optical laser spectroscopy techniques and thin-film characterization methods. Optimized molecular designs lead to evaporated materials with a high, glass-like optical quality that can be combined with existing integrated optics technologies, such as silicon photonics, to add active components for applications such as all-optical switching.