Novel Material Platforms with Reduced Dimensionality for Next Generation Ferroelectric Photonics

铁电铌酸锂晶体(LiNbO_3)和钽酸锂(LiTaO_3)是非常有应用价值的材料。例如，它们充当为我们的信息高速公路供电的电光调制器。它们也被用作频率转换器，以实现紧凑型和高效的绿色激光器。在这个项目中，我们想要探索二维、一维和零维晶体(薄膜、条纹、纳米晶体)的特性。维度的降低保证了新的材料特性，例如，改进的极化行为。我们正在寻找基本的问题，例如，表面是如何终止的：预计表面附近的结构变化，以及缺陷和局部电荷积累可能在这些小长度尺度上发挥重要作用。本课程将使用几种实验光谱和显微方法，并结合理论研究的发展。这些结果可能导致新的应用，例如超快电光调制和太赫兹波的产生。互补的跨大西洋团队(迪尔夫，利哈伊大学，光谱学；基普，汉堡，集成光学；BUSE，波恩，光敏和晶体缺陷；索勒，帕德博恩，非线性光学)非常适合成功完成这一具有挑战性的项目。

Ferroelectric lithium niobate crystals (LiNbO3) as well as lithium tantalate (LiTaO3) are very relevant materials for applications. They serve, e.g., as electro-optic modulators powering our information highways. They are also employed as frequency converters for realizing compact and efficient green lasers. Within the project we want to explore the peculiarities of two-, one-, and zero-dimensional crystals (films, stripes, nanocrystals). The reduction of the dimensionality promises new material properties, e.g., an improved poling behavior. We are looking for the fundamental issues, e.g., how the surfaces are terminated: Structural changes in proximity of the surface are expected, and defects and local charge accumulations may play an important role on these small length scales. Several experimental spectroscopic and microscopic methods will be employed, in conjunction with the development of theoretical considerations. The results may lead to new applications, e.g., ultrafast electro-optic modulation and the generation of terahertz waves. The complementary transatlantic team (Dierolf, Lehigh University, spectroscopy; Kip, Hamburg, integrated optics; Buse, Bonn, photosensitivity and crystal defects; Sohler, Paderborn, nonlinear Optics) is ideally suited to work successfully on this challenging project.