Coherent terahertz emission from coupled quantum wells with exciton effects
Coherent terahertz emission from coupled quantum wells with exciton effects
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具有激子效应的耦合量子阱的相干太赫兹发射
DOI：
10.1364/josab.11.002508
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发表时间：
1994
影响因子：
1.9
通讯作者：
S. Chuang
中科院分区：
文献类型：
--
作者：
Chaiyuth Chansungsan;L. Tsang;S. Chuang
我们建立了一个理论模型来研究最近观测到的GaAs-Ga_（0. 8）Al_（0. 2）As非对称耦合量子阱结构的太赫兹电磁脉冲发射。我们使用一个多子带模型，考虑到所有的电子和空穴之间的库仑相互作用，特别是激子效应。计算结果表明，太赫兹辐射来源于窄阱中重空穴激子之间的量子拍频，随着外加直流电场的增加，太赫兹辐射在耦合量子威尔斯阱中转移到两个共振耦合激子态，在宽阱中转移到重空穴激子态.此外，激子，带间和子带间的退相时间决定的辐射场的特性。理论计算结果与已有的实验结果符合得很好。
We have developed a theoretical model for investigating the recent observation of terahertz electromagnetic pulse emission from GaAs–Ga0.8Al0.2As asymmetric coupled-quantum-well structures. We use a multisubband model that takes into account Coulomb interactions among all electrons and holes, particularly the exciton effects. The calculations indicate that the terahertz emission originates from the quantum beat between heavy-hole excitons in the narrow well and shifts to two resonantly coupled exciton states in the coupled quantum wells and later to heavy-hole excitons in the wide well as the applied dc field is increased. Furthermore, exciton, interband, and intersubband dephasing times determine the characteristics of the radiation fields. The theoretical results are in good agreement with those of previous experiments.