Dispersion dynamics of quantum cascade lasers
Dispersion dynamics of quantum cascade lasers
复制标题
量子级联激光器的色散动力学
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
Q. Hu
中科院分区：
文献类型：
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作者：
D. Burghoff;Yang Yang;J. Reno;Q. Hu
任何非线性光学过程效能的关键参数是群速度色散。在量子级联激光器（qcl）中，最近已经有几个利用中红外和太赫兹非线性的设备的演示。虽然量子晶体的增益已经得到了很好的研究，但对色散的研究却少得多，关于它的动力学和精确起源还存在几个问题。在这项工作中，我们使用时域光谱来研究宽带太赫兹qcl的色散，并证明了材料和子带间跃迁的贡献是相关的。我们表明，与激光增益（被限制在激光阈值以上的固定值）相反，色散甚至在阈值以上也随偏置变化，这是子带间种群移动的结果。最后，我们还研究了高阶色散在qcl中的作用，并讨论了我们的结果对利用非线性效应的器件的影响，如频率梳。
A key parameter underlying the efficacy of any nonlinear optical process is group velocity dispersion. In quantum cascade lasers (QCLs), there have been several recent demonstrations of devices exploiting nonlinearities in both the mid-infrared and the terahertz. Though the gain of QCLs has been well studied, the dispersion has been much less investigated, and several questions remain about its dynamics and precise origin. In this work, we use time-domain spectroscopy to investigate the dispersion of broadband terahertz QCLs, and demonstrate that contributions from both the material and the intersubband transitions are relevant. We show that in contrast to the laser gain—which is clamped to a fixed value above lasing threshold—the dispersion changes with bias even above threshold, which is a consequence of shifting intersubband populations. In conclusion, we also examine the role of higher-order dispersion in QCLs and discuss the ramifications of our result for devices utilizing nonlinear effects, such as frequency combs.
影响因子：
35
作者：
Barbieri, Stefano;Ravaro, Marco;Davies, A. Giles
通讯作者：
Davies, A. Giles