2D polaritons for optoelectronic devices and networks

信息增长率相当于每年增长19%，到2022年底达到100泽字节，快速信息处理需要新型光电工具。随着信息的不断产生和流动，提高处理信息的设备的比特率对于可持续的未来是必不可少的。通常情况下，光信号-光子-通过光纤链路发送，这是大多数互联网流量流动的方式。然而，除非光子耦合到传播它们的介质，否则光子之间不会相互作用。一种方法是将光转换为电子信号，并用传统电子学处理信号。然而，在这种情况下，欧姆损耗降低了能效，处理速度由电子时标定义。一种独特的处理光的方式依赖于强烈的光-物质耦合。当光子与半导体中的光学跃迁和粒子强烈耦合时，它们就变成了混合的光-物质粒子--极化子。偏振子获得非线性，并允许以全光学方式进行信息处理。这一过程的效率在很大程度上取决于用于制造光学设备的材料的多体性质。该项目旨在通过利用半导体双层中的多体相互作用来开发一种独特的光电子器件家族。最近的研究结果表明，在过渡金属二卤化物(TMDCs)体系中，当这些2D材料掺杂过量电荷(例如，自由电子)时，会产生高度非线性的极化响应。在双层几何结构中，它们揭示了基于与电子相关的束缚电子-空穴对的各种层内和层间准粒子的动物园。通过将这些准粒子耦合到光，我们预计强耦合和多体相互作用将导致极化子非线性的游戏规则的增加。然而，要了解这一物理学，需要开发新的理论工具，能够捕捉到这样一个系统中的强关联。在这个项目中，我们的目标是发展过渡金属二卤化物中2D极化子的理论描述，并提出使用极化子多体相互作用的光电子器件的蓝图。我们的项目围绕三个目标构建。我们将建立掺杂TMDC双层膜的非线性响应的理论描述，以表征二维极化子的多体相互作用。我们将研究掺杂TMDC双层膜的非平凡输运性质，以设计基于多体相互作用的极化子电路。我们将利用TMDC异质双层膜中的高度非线性极化子晶格来开发极化子计算网络。因此，我们将为未来基于高度非线性双层系统的2D极化子器件奠定基础。

The rate of information growth corresponds to an annual increase of 19%, reaching 100 zettabytes by the end of 2022, and novel optoelectronic tools are required for fast information processing. With perpetual generation and flow of information around, increasing the bit rates of devices that process information is imperative for sustainable future. Typically, optical signals - photons - are sent over fibre links, and that is how majority of internet traffic flows. However, photons do not interact with each other, unless they couple to a medium in which they propagate. One way to act is converting light into electronic signals, and processing signals with conventional electronics. However, in this case Ohmic losses reduce energy efficiency and processing speed is defined by electronic timescales. A distinct way to process light relies on strong light-matter coupling. When photons are coupled strongly to optical transitions and particles in semiconductors, they become hybrid light-matter particles - polaritons. Polaritons acquire nonlinearity and allow for information processing in an all-optical way. The efficiency of this process largely depends on many-body properties on materials used for building optical devices.The project aims to develop a distinct family of optoelectronic devices by exploiting many-body interactions in semiconducting bilayers. Recent results show a highly nonlinear polaritonic response in systems of transition metal dichalcogenides (TMDCs) when these 2D materials are doped with excessive charge (for instance, free electrons). In bilayer geometry, they reveal a zoo of various intralayer and interlayer quasiparticles based on bound electron-hole pairs correlated with electrons. By coupling these quasiparticles to light, we expect that strong coupling merged with many-body interactions will lead to game-changing increase of polaritonic nonlinearity. However, accessing this physics requires developing new theoretical tools that can capture strong correlations in such a system. Many other properties needed for building polaritonic circuits and processing units are yet to be explored.In the project, we aim to develop a theoretical description of 2D polaritons in transition metal dichalcogenides and propose blueprints for optoelectronic devices that use polaritonic many-body interactions. Our project is structured around three objectives.1. We will develop a theoretical description of nonlinear response in doped TMDC bilayers in order to characterise many-body interactions of 2D polaritons.2. We will study nontrivial transport properties of doped TMDC bilayers to design polaritonic circuits based on many-body interactions.3. We will use highly nonlinear polaritonic lattices in TMDC heterobilayers to develop polaritonic computational networks.As a result, we will develop the background for future 2D polaritonic devices based on highly nonlinear bilayer systems.