基于天文观测的InGaAs/AlAsSb级联激光器的机理和性能研究

In space about interstellar dust cloud emit 40000 types of most spectral lines in the terahertz band, now only about thousands of spectral lines have been identified.This project is guided by infrared astronomical observation, the detection of high spectral resolution of terahertz spectrum requires heterodyne mixing receiver, and the infrared band quantum cascade laser is an important component of terahertz heterodyne mixer receiver, the main research direction is to improve the conversion efficiency and reduce the loss, improve the physical.properties of the material, get the design method of cascade structure and optimize the preparation technology, research around the antimony model cascade laser control loss of key scientific problems in quantum cascade material process and carrier transport behavior, to achieve a wide tuning range, high beam quality and high stability of antimonide laser, and the use of distributed feedback quantum cascade lasers for application of heterodyne mixing integrated receiver local oscillator, it has laid some foundation for the infrared detection of weak signal in special fields such as astronomical observation and deep space exploration in china.

太空中星际尘云大约发射出40000种光谱线大部分在太赫兹波段，现在只有大约几千种谱线已经鉴别，但是由于红外技术在军事上重要应用，相关核心器件的材料、芯片和电路等方面国外一直对我国实现技术封锁，因此也限制了我国红外天文观测方面的研究进展。本项目红外天文观测为导向，围绕太赫兹量子级联激光器与超导热电子混频器集成高分辨率频谱仪核心是外差混频接收机，对太赫兹本振源提出很高的性能要求，以提高器件电光转换效率及降低损耗为主要研究方向，改善锑化物材料物性、获得级联结构设计方法、优化制备技术，围绕级联材料中量子过程与载流子输运行为、级联激光器模式损耗的控制等关键科学问题开展研究，实现宽调谐范围、高光束质量、高稳定性激射波长在3-5μm量子级联半导体激光器，做为宽带高灵敏度的混频器和单模输出功率稳定并且输出较小频宽，自主研发近红外探测太赫兹量子级联激光器作为相干光源，促进天文红外探测系统的技术发展。

本项目针对大规模多像元集成化太赫兹混频器接收机进行研究，采用太赫兹量子级联激光器作为相干光源，利用分布反馈式量子级联激光器及高灵敏度太赫兹热电子混频器，在天体物理和大气科学等各种高分辨率、高灵敏度的探测具有很高的应用价值。基于锑化物材料研究InGaAs/AlAsSb QCL 级联结构的高性能3-5μm 半导体红外波段激光器，开辟半导体中红外激光器件的新领域，实现基于级联激光器的太赫兹外差接收机的设计和研究，为我国天文观测和深空探测等特殊领域极弱信号红外探测需求奠定一些前期基础。研制出InGaAs/AlAsSb QCL 器件原型，实现激射波长在3-5μm 一系列波长半导体激光器的室温激射，脉冲峰值功率高于10W，功率转换效率大于10％，实现宽调谐范围、高光束质量、高稳定性的级联激光器，制备了双周期叠加的分布反馈光栅差频太赫兹QCL并进行了测试，器件在液氮温度下输出的平均功率为2.73nW，峰值功率为182nW，并实现太赫兹量子级联激光器为本振源的外差混频集成接收机应用。