Predicting Optical Switching of Phase-change Materials for Nanophotonic Applications

预测纳米光子应用相变材料的光学开关

• 批准号: 518913417
• 负责人: Privatdozent Dr. Dmitry Chigrin
• 金额: --
• 依托单位: DWI - Leibniz-Institut für Interaktive Materialien e.V.
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/518913417?language=en
• 关键词: Predicting; Optical; Switching; Phase; change

Metasurfaces (MSs) provide comprehensive control over light fields by manipulating the amplitude, phase and polarization of light. This is achieved by exciting resonances of individual metallic or dielectric nanoresonators ("meta-atoms") placed on a surface. Optical instruments based on MSs can therefore be much thinner than conventional optical elements (e.g., glass lenses). By incorporating active elements such as chalcogenide phase-change materials (PCMs), MSs can still be adjusted after fabrication. PCMs can be switched non-volatile between amorphous and crystalline phases, which have drastically different optical properties, especially in the infrared spectral range. Recently, we have shown that it is possible to tune MSs at the meta-atom scale with focused visible light. By changing the PCM phase at the meta-atom level, it is possible to reconfigure - or "program" - MSs after fabrication and dramatically increase their usability and versatility. Due to the general non- stationary nature of the switching process and the complexity of the meta-atom design, the deposited energy in the PCM is inhomogeneous and the resulting phase transition is spatially non- uniform. The drastic changes in material properties during the phase transition further lead to locally nonuniform time-dependent changes in absorbed energy and thermal conduction. Simple theoretical approximations that show good predictions, e.g., for switching complete MS, are not sufficient to describe phase transitions on the meta-atom length scale. The overall goal of this project is to optimize the optical switching of MSs based on PCMs. This is quite different from the switching of PCMs previously studied in optical data storage, where only the lateral contrast change was important. In contrast, it is now necessary to precisely control the 3D crystallization within a PCM-MS, where even the smallest changes in crystallization can lead to a drastic change in optical behavior. To this end, we will develop a complex, self-consistently coupled multiphysics simulation model. Experimental and theoretical work will be closely linked. Verification of the simulations by experimental investigations will allow the necessary understanding to be developed and this knowledge to be translated into a comprehensive simulation model. The implementation of this understanding for optical switching will enable a dramatic increase in the lifetime and switching stability of novel optical devices such as ultrathin adjustable lenses. The same concepts can then be applied to other PCM-incorporating systems, such as tunable waveguides in integrated photonics.

超表面（MS）通过操纵光的振幅、相位和偏振来提供对光场的全面控制。这是通过激发放置在表面上的单个金属或电介质纳米谐振器（“元原子”）的谐振来实现的。因此，基于MS的光学仪器可以比常规光学元件薄得多（例如，玻璃透镜）。通过结合诸如硫族化物相变材料（PCM）的有源元件，MS在制造之后仍然可以被调节。PCM可以在非晶相和晶相之间非挥发性地切换，这具有显著不同的光学性质，特别是在红外光谱范围内。最近，我们已经表明，它是可能的元原子尺度的调谐MS与聚焦可见光。通过在元原子水平上改变PCM相位，可以在制造后重新配置或“编程”MS，并显著提高其可用性和多功能性。由于切换过程的一般非平稳性质和元原子设计的复杂性，PCM中的沉积能量是不均匀的，并且所得到的相变是空间不均匀的。相变过程中材料性质的剧烈变化进一步导致吸收能量和热传导的局部非均匀时间依赖性变化。显示良好预测的简单理论近似，例如，对于切换完全MS，不足以描述元原子长度尺度上的相变。本项目的总体目标是优化基于PCM的MS光交换。这与以前在光学数据存储中研究的PCM的切换完全不同，在光学数据存储中，只有横向对比度变化是重要的。相比之下，现在有必要精确控制PCM-MS内的3D结晶，其中即使是最小的结晶变化也会导致光学行为的急剧变化。为此，我们将开发一个复杂的，自洽耦合多物理场模拟模型。实验和理论工作将紧密相连。通过实验研究验证模拟将允许开发必要的理解，并将这些知识转化为全面的模拟模型。实现这种理解的光开关将使一个戏剧性的增加寿命和开关稳定性的新型光学器件，如可调透镜。然后，相同的概念可以应用于其他PCM合并系统，例如集成光子学中的可调谐波导。