Renormalization and Phase Transitions of Excitons in 2D Nanostructures: Photonics at the University of Pittsburgh

二维纳米结构中激子的重正化和相变：匹兹堡大学的光子学

• 批准号: 0102457
• 负责人: David Snoke
• 金额: $ 31.5万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0102457&HistoricalAwards=false
• 关键词: Renormalization; Phase; Transitions; Excitons; 2D

This project focuses on the nonlinear optical properties of excitons in GaAs and InGaAs coupled quantum wells. When an electric field is applied normal to the wells, the electrons and holes in excitons in these structures become spatially separated, leading to several nonlinear effects. One specific project goal is to create excitonic circuits by which excitons are manipulated by an electric field just like free carriers. This involves modeling the effects of inhomogeneous electric field and stress and developing ways to increase the mobility of excitons in these structures. This task involves a collaboration with sample fabricators. A second goal is to work toward an efficient, room-temperature optical transistor based on this type of quantum well structure. In this scheme one light beam switches another light beam on and off. This involves understanding the many-body renormalization effects of the excitons in these structures, a goal that will be pursued in collaboration with several theorists. This project also includes a substantial commitment to undergraduate science education. An undergraduate Certificate in Photonics program was begun at the University of Pittsburgh under a previous NSF grant. The present project includes efforts to expand that program by creating opportunities for several undergraduates to do research in photonics.When light is absorbed in a semiconductor, the photon particles can be changed into a new type of energy particle known as an exciton. An exciton carries optical energy like a photon but moves through the semiconductor crystal like an electron. By fabricating special layered structures known as double quantum wells, we can cause these exciton particles to move in response to stress and electric field. In this project we study the properties of excitons in double quantum wells, with the aim of creating circuits for these optical particles similar to electronic circuits. The wavelength of the excitons in these structures can also be very sensitive to the intensity of light that hits them. We hope to use this effect to develop an optical transistor, in which one light beam switches another light beam on and off, just as an electronic transistor switches an electrical signal on and off. These effects are part of the field of "photonics," in which devices are made which use photons just as electronics uses electrons. This field is a growing sector of our economy, as the increased need for fast communications pushes technology to optical rather than electronic signals. This project involves not only research in photonics, but also a substantial commitment to photonics education. An undergraduate Certificate in Photonics program was begun at the University of Pittsburgh under a previous NSF grant. The present project includes efforts to expand that program. In particular, this project creates the opportunity for several undergraduates to do research in photonics.

本计画主要研究砷化镓及铟镓砷耦合量子威尔斯井中激子的非线性光学性质。当电场垂直于威尔斯施加时，这些结构中的激子中的电子和空穴在空间上分离，导致几种非线性效应。 一个具体的项目目标是创建激子电路，通过激子电路，激子就像自由载流子一样被电场操纵。这包括模拟不均匀电场和应力的影响，并开发增加这些结构中激子迁移率的方法。这项任务涉及与样品制造商的合作。第二个目标是基于这种类型的量子阱结构，致力于开发一种高效的室温光学晶体管。在这个方案中，一个光束打开和关闭另一个光束。这涉及了解这些结构中激子的多体重整化效应，这是一个将与几位理论家合作追求的目标。该项目还包括对本科科学教育的实质性承诺。 在以前的NSF资助下，匹兹堡大学开始了光子学本科证书课程。 目前的项目包括努力扩大该计划，为几个本科生创造机会，做光子学的研究。当光被吸收在半导体中，光子粒子可以变成一种新型的能量粒子称为激子。激子像光子一样携带光能，但像电子一样在半导体晶体中移动。通过制造称为双量子威尔斯的特殊分层结构，我们可以使这些激子粒子响应应力和电场而移动。在这个项目中，我们研究了双量子威尔斯中激子的性质，目的是为这些光学粒子创建类似于电子电路的电路。这些结构中激子的波长也可以对撞击它们的光的强度非常敏感。 我们希望利用这种效应来开发一种光学晶体管，在这种晶体管中，一束光可以打开和关闭另一束光，就像电子晶体管打开和关闭电信号一样。这些效应是“光子学”领域的一部分，在光子学中，使用光子的器件就像电子学使用电子一样。 这一领域是我们经济中一个不断增长的部门，因为对快速通信的需求不断增加，将技术推向光学而不是电子信号。该项目不仅涉及光子学的研究，还涉及光子学教育的实质性承诺。在以前的NSF资助下，匹兹堡大学开始了光子学本科证书课程。目前的项目包括努力扩大这一方案。特别是，这个项目为几个本科生创造了在光子学方面进行研究的机会。