Temperature-Driven Enhancement of the Stimulated Emission Rate in Terahertz Quantum Cascade Lasers
Temperature-Driven Enhancement of the Stimulated Emission Rate in Terahertz Quantum Cascade Lasers
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DOI：
10.1109/jqe.2016.2631899
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发表时间：
2017-01-01
影响因子：
2.5
通讯作者：
Flores, Yuri V.
中科院分区：
文献类型：
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作者：
Albo, Asaf;Flores, Yuri V.
我们分析了太赫兹量子级联激光器（THz-QCL）的光输出功率的温度依赖性，并证明了由热激活电子从较低的激光水平泄漏到连续谱触发的受激发射率的增强。与常识预期相反，我们发现，这种泄漏通道有助于积极的THZ-QCL的温度性能。我们表明，这种泄漏机制是缺少的组件来解释光输出功率的全部温度依赖性，因为它抵消了粒子数反转减少，所产生的非辐射电子散射从上到下的激光状态。我们分析了实验的光输出功率与温度数据的3.87太赫兹发射设备具有高度对角光学过渡在很宽的温度范围内（10-180 K），并显示如何热激活泄漏的电子从较低的激光水平导致一个几乎恒定的输出功率高达类似的温度为120 K。这些结果提出了一个问题，即是否可以开发利用这种效应的新设计方法，以证明具有更高最高工作温度的器件。
We analyze the temperature dependence of the light output power of terahertz quantum cascade lasers (THz-QCLs) and demonstrate an enhancement of the stimulated emission rate triggered by thermally activated electron leakage from the lower laser level into the continuum. Contrary to common sense expectation, we find that this leakage channel contributes positively to the temperature performance of THz-QCLs. We show that this leakage mechanism is the missing component to explain the full temperature dependence of the light output power as it counteracts the population inversion reduction that arises from non-radiative electron scattering from the upper into the lower laser state. We analyze experimental light output power versus temperature data for a 3.87-THz-emitting device with highly diagonal optical transition over a wide temperature range (10-180 K) and show how thermally activated leakage of electrons from the lower laser level leads to a nearly constant output power up to a temperature of similar to 120 K. These results open the question if new design approaches that exploit this effect can be developed in order to demonstrate devices with higher maximum operating temperature.