Polariton lasing and Bose-Einstein condensation in an electrically pumped system

我们打算演示第一个电注入极化激元激光器。将确定激光器运行的物理基础，以及导致其最佳性能的因素。偏振子激光器是一种新的器件概念，它具有极低阈值相干光发射的前景，同时对应于固体系统中的非平衡玻色-爱因斯坦凝聚(BEC)。半导体微腔中激子与光子的强耦合导致了新型准粒子激子-极化子的形成。这类极化子表现出特有的玻色子性质，如宏观占据单个量子态和具有长时间和空间相干性的系统中的玻色子纠缠。由于极化子的光子成分，宏观上占据的极化子态发射相干光，并形成了一种新型光源--极化子激光器，在这种光源中，相干光的发射不需要布居反转。直到最近，这一领域的几乎所有工作都是在光激发条件下进行的。从器件的角度来看，我们最近观察到了极化电子态在电注入下的光发射，这给了我们新的动力，紧随其后的是另外两个小组。这项提议旨在利用我们在该领域的最新成就和整体专业知识，实现重要的世界第一，即第一个电注入极化激光，这是这些新设备在现实世界中应用所需的。

We propose to demonstrate the first electrically injected polariton laser. The physics underlying the operation of the laser, and the factors which lead to its optimum performance will be determined. The polariton laser is a new device concept which holds the promise of very low threshold coherent light emission, at the same time as corresponding to non-equilibrium Bose-Einstein condensation (BEC) in a solid state system. The strong coupling between excitons and photons in semiconductor microcavities leads to the formation of novel quasi-particles, exciton-polaritons. Such polaritons exhibit characteristic bosonic properties such as macroscopic occupation of individual quantum states and BEC in a system with long temporal and spatial coherence. Due to the photonic component of the polaritons, the macroscopically occupied polariton state emits coherent light, and forms the basis of a new type of light source, the polariton laser, in which coherent light is emitted without the need for population inversion. Until very recently nearly all work in this field has been carried out under conditions of optical excitation. From the device perspective, new impetus has been given by our recent observation of light emission from polariton states under electrical injection, followed very soon after by two other groups. This proposal aims to capitalise on our recent achievements and overall expertise in the field, to realise an important world first, the first electrically injected polariton laser, as required for real world applications of these novel devices.