Bose-Einstein condensation of exciton polaritons
Bose-Einstein condensation of exciton polaritons
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DOI：
10.1038/nature05131
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发表时间：
2006-09-28
期刊：
影响因子：
64.8
通讯作者：
Dang, Le Si
中科院分区：
文献类型：
--
作者：
Kasprzak, J.;Richard, M.;Dang, Le Si
相变到量子凝聚相-如玻色-爱因斯坦凝聚（BEC），超流性和超导性-长期以来一直吸引着科学家，因为它们将纯量子效应带到了宏观尺度。例如，BEC在温度低于200纳开尔文的铷原子的稀原子气体中得到了著名的证明。人们一直致力于寻找一种能够发生BEC的固态系统。有前途的候选系统是半导体微腔，其中光子被限制并与电子激发强烈耦合，导致激子极化激元的产生。这些玻色子准粒子比铷原子轻10 - 9倍，因此理论上允许BEC在标准低温下发生。在这里，我们详细介绍了一套全面的实验提供令人信服的证据BEC的极化激元。在临界密度以上，我们观察到大量占领的基态发展从极化激元气体在19 K的热平衡，时间相干性的增加，和建立的远程空间相干性和线性偏振，所有这些都表明自发发作的宏观量子相位。
Phase transitions to quantum condensed phases - such as Bose - Einstein condensation (BEC), superfluidity, and superconductivity - have long fascinated scientists, as they bring pure quantum effects to a macroscopic scale. BEC has, for example, famously been demonstrated in dilute atom gas of rubidium atoms at temperatures below 200 nanokelvin. Much effort has been devoted to finding a solid-state system in which BEC can take place. Promising candidate systems are semiconductor microcavities, in which photons are confined and strongly coupled to electronic excitations, leading to the creation of exciton polaritons. These bosonic quasi-particles are 10 9 times lighter than rubidium atoms, thus theoretically permitting BEC to occur at standard cryogenic temperatures. Here we detail a comprehensive set of experiments giving compelling evidence for BEC of polaritons. Above a critical density, we observe massive occupation of the ground state developing from a polariton gas at thermal equilibrium at 19 K, an increase of temporal coherence, and the build-up of long-range spatial coherence and linear polarization, all of which indicate the spontaneous onset of a macroscopic quantum phase.