基于衍射光栅耦合输出的一级分布反馈太赫兹量子级联激光器
Received:April 05, 2017  Revised:September 19, 2017  点此下载全文
引用本文:朱欢,王芳芳,颜全,俞辰韧,常高垒,陈建新,徐刚毅,何力.基于衍射光栅耦合输出的一级分布反馈太赫兹量子级联激光器[J].Journal of Infrared and Millimeter Waves,2017,36(6):706~712
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Author NameAffiliationE-mail
ZHU Huan Key Laboratory of Infrared Material and DetectorsShanghai Institute of Technical Physics, Chinese Academy of Sciences zhuhuanchuan@126.com 
WANG Fang-Fang Shanghai Institute of technical Physics, Chinese Academy of Sciences  
YAN Quan Shanghai Institute of technical Physics, Chinese Academy of Sciences  
YU Chen-Ren Shanghai Institute of technical Physics, Chinese Academy of Sciences  
CHANG Gao-Lei Shanghai Institute of technical Physics, Chinese Academy of Sciences  
CHEN Jian-Xin Shanghai Institute of technical Physics, Chinese Academy of Sciences  
XU Gang-Yi Shanghai Institute of technical Physics, Chinese Academy of Sciences gangyi.xu@mail.sitp.ac.cn 
HE Li Shanghai Institute of technical Physics, Chinese Academy of Sciences  
基金项目:中国科学院百人计划项目,国家自然科学基金项目(面上项目)61574149,国家重点研发计划2016YFB0402303、2016YFA0202200,预研项目41414020901,中科院创新实验室基金项目CXJJ-15S098
中文摘要:对比研究了两种不同结构的太赫兹波段的双金属波导一级分布反馈量子级联激光器(THz-DFB-QCL)。常规结构通过解理腔面形成边发射,但由于腔面的高反射率和反射波相位的随机性,无法获得单模激射。在我们首次提出并实现的基于衍射光栅耦合输出的THz-DFB-QCL中,太赫兹波通过衍射光栅而非解理腔面形成出射。计算表明,优化衍射光栅的结构可实现约70%的激光输出效率和小于1%的反射率,激光发散角约为10×50°。极低的反射率可以有效抑制反射波对腔内谐振的干扰,是获得单模激射的关键。实验上,利用衍射光栅耦合输出的激光器实现了频率约2.58 THz的稳定单模激光,边模抑制比达23 dB,光束分布与理论计算相吻合。得益于较好的衍射效率和光束准直性,相比于常规的解理腔面边发射激光器,通过衍射光栅耦合输出显著提升了激光功率。
中文关键词:太赫兹  一级分布反馈  量子级联激光器  衍射光栅
 
Terahertz first-order distributed feedback quantum cascade laser with light extraction via a diffraction grating
Abstract:We have studied two different kinds of terahertz first-order distributed feedback quantum cascade lasers (THz-DFB-QCL), both of which are based on a metal-metal waveguide. In the convenient edge-emitting laser structure, single mode emission is not obtainable due to a high reflectivity and a random phase of the reflected wave caused by the cleaved facet. To realize stable single-mode emission, we have demonstrated for the first time THz-DFB-QCLs in which THz wave is extracted via a diffraction grating. Our simulations illustrate that an optimized diffraction grating will give rise to a diffraction efficiency of about 70%, and a reflectivity less than 1%. It will also result in a laser beam pattern with a low divergence angle of 10×50°. Such a low reflectivity will keep the mode oscillation inside the DFB grating not disturbed, which is crucial to realize stable single-mode emission. Experimentally, by utilizing a diffraction grating to extract THz wave, we have realized THz-DFB-QCLs with stable single-mode emission near 2.58 THz and the side-mode-suppression-ratio is about 23dB. The measured laser beam pattern is in good agreement with the calculations. Most importantly, due to the good diffraction efficiency and beam directionality, the diffraction grating based THz-DFB-QCL significantly improves the output power compared with the edge-emitting counterpart.
keywords:terahertz  first-order distributed feedback  quantum cascade lasers  diffraction grating
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