二阶分布反馈太赫兹量子级联激光器的光学特性  

Optical Characteristics of Second-Order Distributed Feedback Terahertz Quantum Cascade Laser

作　　者：李鑫[1] 王健[1] 杨宁[2] 楚卫东[2] Li Xin;Wang Jian;Yang Ning;Chu Weidong(Institute of Optical Information, Key Lab of Education Ministry on Luminescence and Optical Information Technology, Beijing Jiaotong University, Beijing 100044, China;Institute of Applied Physics and Computational Mathematics, Beijing 100088, China)

机构地区：[1]北京交通大学发光与光信息技术教育部重点实验室,光信息科学与技术研究所,北京100044 [2]北京应用物理与计算数学研究所,北京100088

出　　处：《光学学报》2018年第4期248-254,共7页Acta Optica Sinica

基　　金：国家重点研发计划(2013CB632805); 国家重大科学仪器设备开发专项(2011YQ130018); 北京应用物理与计算数学研究所所长青年基金(ZYSZ1518-16)

摘　　要：太赫兹量子级联激光器(THz QCL)的增益谱较宽,使用普通法布里-珀罗腔时一般为多纵模激射。二阶分布反馈THz QCL可利用表面辐射损耗消除模式简并,实现单纵模激射。采用耦合模理论对单面金属波导二阶分布反馈THz QCL基本参数的计算公式进行了理论推导,并研究了光栅结构参数对其耦合系数、阈值增益、光子密度及外微分量子效率等参数的影响。在以自然解理面为端面的波导上刻蚀占空比约为0.15、有源区深度为0.5μm的光栅时,激光器的阈值增益较低,腔内光子密度分布相对均匀,能够实现单纵模激射。The terahertz quantum cascade laser（THz QCL）has a wide gain spectrum,and the emission is often multiple-longitudinal mode when using the conventional Fabry-Perot cavity.A second-order distributed feedback THz QCL can eliminate the mode degeneracy to realize the single longitudinal mode lasing by means of surface radiation loss.Based on the coupled-mode theory,the computational formulas of the basic parameters for the second-order distributed feedback THz QCL with the single-side metal waveguide are deduced.The influences of the grating structure parameters on the coupling coefficients,threshold gain,photon density,and external differential quantum efficiency is investigated.When the grating with a duty cycle of about 0.15 and a depth in the active region of 0.5μm is etched on the waveguide with a natural cleavage plane,the threshold gain is low,the photon density distribution within the cavity is uniform,and the single longitudinal mode emission can be achieved.

关 键 词：太赫兹 量子级联激光器 耦合模理论 二阶光栅 单纵模激射 

分 类 号：TN248.4[电子电信—物理电子学]