Materials World Network: Novel Material Platforms with Reduced Dimensionality for Next Generation Ferroelectric Photonics

非技术描述：铁电材料被发现在无数的，广泛的应用，例如：作为条形码阅读器在杂货店结账和作为设备使今天的互联网成为可能。这些应用中的许多都利用了将相关器件特征的尺寸减小到微米尺寸的能力，并通过适当排列铁电畴来定制材料的特性。然而，现有的器件是基于厚度为0.5毫米或更厚的大块晶体或晶圆。这限制了生产尺寸更紧凑或功能更易于调整的设备的能力。这项工作旨在开发具有降低尺寸的新平台的材料基础，以克服这些限制。这项材料世界网络资助的PI与德国的两个小组（波恩大学的Karsten Buse教授和汉堡赫尔穆特施密特大学的Detlef Kip教授）合作，这两个小组由德国研究基金会（DFG，德国研究基金会）支持。通过这个国际项目，本科生、研究生和博士后学者通过所有参与组织的旅行交流和研讨会，获得了一个独特的视角来进行全球互动。本科生研究和交流是这项合作的重要组成部分，涉及里海大学的本科生，尤其针对代表性不足的学生。该团队还通过为高中生组织年度外展研讨会，为里海科学外展计划做出贡献。技术细节：该项目侧重于开发两种新型材料平台：(1)绝缘体上铌酸锂平台（LNOI），利用3英寸晶圆尺寸的晶体片和光学限制小于1微米的光子线。(2)粒径在10 ~ 100 nm之间的单畴纳米晶体。该团队采用多方面的方法，从解决由于降低维数和增加表面和界面作用而导致的体特性变化的基础科学问题，到开发专门适用于域图像化和铁电纳米粒子排列的方法，再到演示诸如w- thz源和其他非线性频率转换器等设备。该团队利用其在硅片级氧化硅上铌酸锂的制造以及单分散铌酸锂纳米晶体的制备方面的专业知识，并将利用表面敏感的表征方法，如近场紫外拉曼光谱，高分辨率透射电子显微镜和低能离子散射。在一种新型的光镊仪器中，将研究操纵纳米晶体取向的可能性，该仪器可以三维控制光偏振和原位拉曼表征。

NON-TECHNICAL DESCRIPTION: Ferroelectric materials are found in countless, widespread applications, e.g.: as barcode readers in grocery checkouts and as the devices that make today's Internet possible. Many of these applications exploit the ability to reduce the size of the relevant device features to micron dimensions and to tailor properties of the material by properly arranging ferroelectric domains. However, existing devices are based on bulk crystals or wafers with thicknesses of 0.5 mm or more. This limits the ability to produce devices that are more compact in size or are easily tunable in their function. This work aims at developing the materials foundations for new platforms with reduced dimensionality to overcome these limitations. The PI of this Materials World Network grant collaborates with two groups in Germany (Prof. Karsten Buse, University of Bonn and Prof. Detlef Kip, Helmut Schmidt University Hamburg) which are supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation). Through this international program, undergraduate, graduate and post-doctoral scholars acquire a unique perspective in interacting globally through travel exchanges and workshops involving all participating organizations. Undergraduate research and exchange is a strong element of this collaboration involving Lehigh's undergraduate students and targeting especially underrepresented students. The team also contributes to the Lehigh Science Outreach program by organizing annual outreach workshops for high school studentsTECHNICAL DETAILS: The project focuses on the development of two novel material platforms: (1) The lithium-niobate-on-insulator platform (LNOI) utilizing 3 inch wafer-sized crystal slices and photonic wires with optical confinement below 1 micron. (2) Single domain nanocrystals in sizes between 10-100 nm. The multifaceted approach of the team spans from solving basic science questions about the changes in bulk properties due to the reduced dimensionality and the increased role of surfaces and interfaces, to the development of specially adapted methods for domain patterning and the alignment of ferroelectric nanoparticles, to the demonstration of devices such as a cw-THz source and other nonlinear frequency converters. The team exploits its expertise in the fabrication of wafer-scale lithium-niobate-on-silicon-oxide as well as in preparation of mono-disperse lithium niobate nanocrystals and will utilize surface sensitive characterization methods such as near-field UV-Raman spectroscopy, high-resolution transmission electron microscopy and low energy ion scattering. The possibility of manipulating the orientation of nanocrystals will be studied in a novel optical tweezers instrument, which allows 3D control of light polarization and in situ Raman characterization.