用于产生太赫兹波的双模半导体激光器技术研究

It plays an important role for THz technology in the applications of object imaging, environmental monitoring, national Security and anti-terrorism, and etc.. However, the low temperature, cost and complicated THz generator hecome the bottleneck of the THz technology. Based on the problem analysis of the state of the art THz generator according to optical heterodyne method, dual-mode VCSEL structure for THz generation was proposed. The additional mode could be realized by adding the cavity length of the VCSEL. The beating frequency could be in the range of THz. The two modes come from the single active region, which indicates the stability of the beating frequency and do not change with the temperature, time, current, and etc, which will solve the problem of stability and noise. Also the efficiency is high compared with the pumping nonlinear crystal. The critical problem for this project is how to design wide refective bandwidth and wide gain spectrum, how to solve the problem between the two mode generation and quantum efficiency, and also corresponding material growth and device fabrication. The final objective is to fabricate the two mode CW VCSEL for THz generation with the power of 1μW above 5THz.

THz技术在物体成像、环境监测、医疗诊断、国家安全以及反恐等领域的发展起着重要的作用，而缺乏室温工作、成本高、系统复杂的THz光源是限制THz技术进一步发展的瓶颈。本项目在充分了解光学方法获得THz辐射源的研究现状和存在的问题基础上，提出了VCSEL结构在单腔下实现稳定、可控、双纵模激射拍频为THz频率的新思想。由于直接发光，不需要泵浦非线性材料，解决现有方案吸收损耗大的问题；由于从单个有源区发射，两个共振的频率差随温度、时间等因素变化较小，可获得较稳定的THz辐射源。在解决宽反射带宽和宽增益谱的结构设计、双模式激光的产生与激光效率矛盾等关键科学问题和材料生长和器件制备的等技术问题，制备出室温直流双共振VCSEL原型器件，差频范围为5～10THz，THz功率>1μW；理论上并在实验上探索并展示差频信号随时间、温度变化相对不变的物理根源和物理效应。

THz技术在物体成像、环境监测、医疗诊断、国家安全以及反恐等领域的发展起着重要作用，而缺乏室温工作、成本高、系统复杂的THz光源是限制THz技术进一步发展的瓶颈。本项目在充分了解光学方法获得THz辐射源的研究现状和存在的问题基础上，提出并掌握了VCSEL结构在单腔下实现稳定、可控、双纵模激射拍频为THz频率的基本原理、设计原则和关键制备工艺技术，国际上第二个团队获得双波长室温激射垂直腔面发射激光器(VCSEL)，拍频差为7.4THz；针对VCSEL双模式激光芯片的特点搭建了可以精细调整偏置电流和温度控制的测试与封装平台，设计并可实现对THz辐射源的同轴结构带控温耦合封装的制备工艺，可实现小批量生产。同时，根据最近VCSEL的发展趋势，我们增加了高速VCSEL的研制内容，实现了17GHz的小信号调制速率，成为国内第一个报道高速VCSEL结果的研究小组。.发表SCI收录学术论文20篇，申请国家发明专利10项，培养博士研究生2名，硕士研究生9名。