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广泛的应用中，例如：作为食品杂货收银台的条形码阅读器，以及作为使今天的互联网成为可能的设备。这些应用中的许多利用了将相关器件特征的尺寸减小到微米尺寸并通过适当地布置铁电域来定制材料属性的能力。然而，现有的器件是基于厚度为0.5 mm或更大的块状晶体或晶片。这限制了生产尺寸更紧凑或功能更容易调节的设备的能力。这项工作旨在为降维的新平台开发材料基础，以克服这些限制。这个材料世界网络的PI赠款与德国的两个组织(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，这两个组织得到了德国研究基金会(DFG)的支持。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，在全球范围内进行互动，获得了独特的视角。本科生研究和交流是这种合作的一个重要组成部分，涉及利哈伊的本科生，并针对特别是代表不足的学生。该团队还通过为高中生组织年度外展研讨会，为LeHigh科学外展计划做出贡献。技术细节：该项目专注于开发两种新型材料平台：(1)利用3英寸晶片大小的晶片和光学限制在1微米以下的光子线的绝缘体上铌酸锂平台(LNOI)。(2)尺寸在10-100 nm之间的单结构域纳米晶。该团队的多方面方法从解决由于表面和界面的降维和作用增加而导致的体属性变化的基础科学问题，到开发专门适应的磁区图案化和铁电纳米粒子的对准方法，到演示诸如CW-THz源和其他非线性变频器等器件。该团队利用其在硅氧化物上制造晶片规模的LiNbate以及制备单分散的LiNbate纳米晶体方面的专业知识，并将利用近场UV-拉曼光谱、高分辨率透射电子显微镜和低能离子散射等表面敏感表征方法。一种新型的光镊仪将研究操纵纳米晶体取向的可能性，该仪器可以实现光偏振的三维控制和原位拉曼表征。

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.