Stimulated emission at transitions between Wannier–Stark ladders in semiconductor superlattices
Stimulated emission at transitions between Wannier–Stark ladders in semiconductor superlattices
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半导体超晶格中万尼尔-斯塔克梯子之间跃迁的受激发射
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
A. Fefelov
中科院分区：
文献类型：
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作者：
A. Andronov;E. P. Dodin;D. I. Zinchenko;Y. Nozdrin;M. Ladugin;A. Marmalyuk;A. Padalitsa;V. Belyakov;I. Ladenkov;A. Fefelov
基于简单GaAs （150 Å，量子阱）/GaAlAs （19 Å，铝含量为12%，势垒）超晶格的新型带内半导体激光器——wanner - stark激光器已经被证明。这些激光器中的放大机制是基于超晶格量子阱中的地面Wannier-Stark能级与应用势下2、3或4个周期的弱填充的Wannier-Stark能级之间的居位反转。在激光芯片中，在电压8,13和20v附近（即在这些超晶格的wanner - stark能级之间的共振附近）发现了多个强激发微波发射区域。受激辐射出现在由芯片及其布线形成的电路中。其中一个芯片在高达150k的温度下（近20v施加到芯片上）的发射频率约为7.3 GHz，估计功率高达1w。已经表明，负电导率负责发射仍然持续在300 K，但发射是看不见的，由于高损耗电路在这个温度下。采用金属有机化学气相沉积法制备了超晶格晶片。它由1000个周期和一个停止层组成，以产生一个金属-超晶格-金属太赫兹谐振器。与谐振器中的损耗相比，太赫兹辐射由于放大率低而未被观察到。根据实验、计算和讨论，在适当优化其参数的情况下，这种超晶格作为千兆赫、太赫兹和更高频率范围的辐射源可以与量子级联激光器竞争。
New intraband semiconductor lasers—Wannier–Stark lasers—based on simple GaAs (150 Å, quantum well)/GaAlAs (19 Å with an aluminum fraction of 12%, barrier) superlattices have been demonstrated. The amplification mechanism in these lasers is based on population inversion between the ground Wannier–Stark level in the superlattice quantum wells and the weakly populated upper Wannier–Stark level in the wells two, three, or four periods down in the applied potential. Multiple regions of intense stimulated microwave emission near voltages of 8, 13, and 20 V (i.e., in the vicinity of resonances between these Wannier–Stark levels of the superlattice) have been discovered in the laser chips. The stimulated emission emerges in the circuit formed by the chip and its wiring. The emission from one of the chips at a temperature of up to 150 K (near 20 V applied to the chip) occurs at a frequency of about 7.3 GHz and has an estimated power of up to 1 W. It has been shown that the negative conductivity responsible for the emission still persists at 300 K but the emission is unseen owing to high losses in the circuit at this temperature. The superlattice wafer has been grown by metalorganic chemical vapor deposition. It consists of 1000 periods and a stop layer, to produce a metal–superlattice–metal terahertz resonator. Terahertz radiation has not been observed owing to a low amplification, as compared to losses in the resonator. According to the performed experiments, calculations, and discussions, such superlattices as radiation sources in gigahertz, terahertz, and higher frequency ranges could compete with quantum cascade lasers under appropriate optimization of their parameters.