Terahertz radiation in semiconductor quantum dots driven by gigahertz waves: The role of tailoring the quasienergy spectrum
Terahertz radiation in semiconductor quantum dots driven by gigahertz waves: The role of tailoring the quasienergy spectrum
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千兆赫波驱动的半导体量子点中的太赫兹辐射：定制准能谱的作用
DOI：
10.1103/physrevb.80.161304
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发表时间：
2009-10
期刊：
影响因子：
--
通讯作者：
Suqing Duan
中科院分区：
文献类型：
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作者：
Weidong Chu;Xian-Geng Zhao;Wei Zhang;Yan Xie;Suqing Duan
由于高功率GHz光源的存在，我们研究了半导体量子点中高次谐波场在GHz波驱动下产生的太赫兹辐射。通过将光学问题映射到传输问题，我们能够揭示太赫兹波产生过程中的几个特征。根据Floquet定理，与粒子输运有关的THz波产生效率由准能谱的带宽决定。我们不仅揭示了光学过程和输运现象之间的有趣关系，而且还找到了产生太赫兹波的最佳条件（对应于共振）和猝灭条件（对应于带塌缩）。这种良好的开关特性（共振态与猝灭态的发射强度之比$\ensuremath{\sim}{10}^{6}$）有助于太赫兹源的设计，并在涉及太赫兹波的纳米器件中具有重要的应用。
We explore the terahertz (THz) radiation from high-order harmonic fields in semiconductor quantum dots driven by gigahertz (GHz) waves, due to the availability of high power GHz sources. By mapping the optical problem to a transport problem, we are able to uncover several features in the THz wave generation processes. With the help of the Floquet theorem, the efficiency of THz wave generation, which is related to the particle transport, is determined by the bandwidth of the quasienergy spectrum. We not only reveal the interesting relation between optical processes and transport phenomena, but also find the optimal conditions (corresponding to resonances) and quench conditions (corresponding to band collapses) for THz wave generation. The nice on/off properties (the ratio of emission intensity at resonance to that at quench condition $\ensuremath{\sim}{10}^{6}$) are helpful for the design of THz source and have important applications in nanodevices with THz wave involved.