Optical and terahertz interactions with phase-change materials and nanostructures

这项申请寻求对光与可调介质(如相变材料(PCM)和纳米结构)之间相互作用的研究提供支持。人们正在研究PCM，以增进凝聚态物理方面的知识，并将其用于数据存储和存储等光学技术。二氧化钒(VO2)是一种重要的相变材料，它的可逆相变可以在快速的时间尺度上通过热或光学诱导。在相变过程中会发生很大的折射率变化，使这种材料能够改变和控制光的流动。其他具有类似性质的材料包括硫系化合物，如Ge2Sb2Te5和AgInSbTe。在近年来PCM经验的基础上，我将探索三个新途径：太赫兹(THz)辐射作为研究材料基本性质的探测器对科学很重要，作为一种能够穿透可见光和红外光不透明材料的成像工具对工业很有用。太赫兹科学的扩展不仅依赖于高效探测器和强大相干源的发展，而且依赖于操纵场的基本部件的可用性，如偏振器、调制器和相位板。为此，研究目标之一是探索PCM如何在快速时间尺度上改变和控制太赫兹辐射的幅度、相位和偏振。近年来，相变显示器引起了人们的极大兴趣，因为超薄彩色显示器是基于白光在PCM薄膜中的干涉效应而被展示出来的。通过在材料的两个相之间切换，反射光谱被移动到不同的颜色坐标。在之前发现VO2会改变光的偏振状态后，我想研究偏振效应，以此作为提高相变显示器性能的一种方法。具有可随大小调节光学特性的金纳米颗粒将与PCM相结合，以进一步增强颜色控制。硅光学元件之所以有趣，是因为它们为光子学和电子学创造了一个接口，而且因为有许多技术可以在纳米级处理材料。这项研究计划的目标之一是研究与硅相连的均匀的PCM薄层如何实现硅光子学的一些基本功能，如控制进出硅和硅波导的光的流动，以及控制光在其中传播的幅度、相位和偏振。该研究项目将通过培训学生从事与基础知识和光学技术相关的研究领域，从而造福社会。鉴于这项研究的应用性质，与工业界合作创造新的光子器件的潜力很大。

This application seeks support for research on the interactions between light and tunable media such as phase change materials (PCM's) and nanostructures. PCM's are being studied to advance knowledge in condensed-matter physics and used in optical technologies such as data storage and memory. One important PCM is vanadium dioxide (VO2), whose reversible phase transition from semiconductor to metal can be induced thermally or optically on rapid time scales. Large refractive index changes occur during the phase transition, making the material capable of modifying and controlling the flow of light. Other materials with similar properties include chalcogenides like Ge2Sb2Te5 and AgInSbTe. Building on the experience gained in recent years with PCM's, I will explore three new avenues: Terahertz (THz) radiation is important to science as a probe to study the fundamental properties of materials, and useful to industry as an imaging tool capable of penetrating materials that are opaque to visible and infrared light. The expansion of THz science has relied not only on the development of efficient detectors and powerful coherent sources, but also on the availability of basic components to manipulate the field, such as polarizers, modulators and phase-plates. To this end, one of the research goals is to explore how PCM's can modify and control the amplitude, phase and polarization of THz radiation on rapid time scales. Phase change displays have generated much interest in recent years, as ultra-thin color displays were demonstrated based on interference effects of white light in PCM films. By switching the material between its two phases, the reflected spectrum was shifted to different color coordinates. Having previously found that VO2 alters the polarization state of light, I would like to investigate polarization effects as a way to enhance the performance of phase change displays. Gold nanoparticles, with optical properties tunable with size, will be combined with PCM's to further enhance coloration control. Silicon optical components are interesting because they create an interface for photonics and electronics, and because of the many technologies available to process the material at the nanometer scale. One goal of this research proposal is to study how thin, uniform layers of PCM's interfaced to silicon can achieve some basic functions of silicon photonics, such as controlling the flow of light in and out of silicon and silicon waveguides, and controlling the amplitude, phase and polarization of the light traveling inside. The research program will benefit society by training students in research fields that are relevant to both fundamental knowledge and optical technology. Given the applied nature of the research, there is significant potential for partnerships with industry for the creation of new photonic devices.