Heterodyne Spectroscopy of Frequency Instabilities in Terahertz Quantum-Cascade Lasers Induced by Optical Feedback
Heterodyne Spectroscopy of Frequency Instabilities in Terahertz Quantum-Cascade Lasers Induced by Optical Feedback
复制标题
DOI：
10.1109/jstqe.2017.2684078
复制
发表时间：
2017-03
影响因子：
4.9
通讯作者：
H. Hübers;H. Richter;R. Eichholz;M. Wienold;K. Biermann;L. Schrottke;H. Grahn
中科院分区：
文献类型：
--
作者：
H. Hübers;H. Richter;R. Eichholz;M. Wienold;K. Biermann;L. Schrottke;H. Grahn
利用高分辨外差光谱技术研究了光反馈对太赫兹量子级联激光器频率稳定性的影响。从两对QCL工作在3.4或4.7太赫兹的发射混合在肖特基二极管和产生的差异频率在千兆赫范围内进行测量。小于1 MHz的高光谱分辨率和1 ms的时间分辨率使我们能够在与光谱学相关的尺度上研究反馈引起的频率不稳定性。在光反馈仅为QCL输出功率的3 × 10−5的情况下，观察到高达70 MHz的频率变化。
We study the influence of optical feedback on the frequency stability of terahertz (THz) quantum-cascade lasers (QCLs) by high-resolution heterodyne spectroscopy. The emission from two pairs of QCLs operating either at 3.4 or at 4.7 THz is mixed in a Schottky diode and the resulting difference frequency in the gigahertz range is measured. The high spectral resolution of less than 1 MHz and a time resolution of 1 ms enable us to investigate feedback-induced frequency instabilities on scales that are relevant for spectroscopy. Frequency changes of up to 70 MHz are observed with an optical feedback of only 3 × 10−5 of the output power of the QCL.