2-3微米宽调谐GaSbBi量子阱外腔激光器研究

Tunable external-cavity lasers (TECLs) are of great significance in many applications such as high sensitivity gas sensing, medical diagnosis and environment monitoring, due to their special features such as single mode, narrow line width and broadband tunable wavelength range. Until now, research and commercial products on TECLs have mainly focused on 1-2μm and 3-10μm wavelength range. The wavelength range of 2-3μm covers fundamental absorption peaks of many important gas molecules. GaSbBi has revealed broad light emission in the 2-3μm wavelength range, making it very promising for realizing TECLs in this wavelength range. In this project we propose for the first time applying dilute bismide as gain medium for TECLs based on its wide gain spectrum, aiming at realizing 2-3μm widely tunable GaSbBi quantum well (QW) TECLs. We originally propose four different GaSbBi QW structures to maximize gain spectral width. The GaSbBi QW laser structures will be grown using molecular beam epitaxy. We will investigate influences of growth conditions on structural, electrical and optical properties and their optimization. We will improve the fabricating process, demonstrate high performance GaSbBi QW TECLs with broad gain and test their performances. We will also investigate the tunability mechanisms of GaSbBi QW TECLs. Finally we will demonstrate 2-3μm continuous tuning GaSbBi QW TECLs with a tunable range >200nm, single mode output power >10mW and side-mode suppression ratio >30dB.

可调谐外腔激光器具有单纵模输出、线宽窄、调谐范围宽等优点，目前科研和商用可调谐外腔激光器主要集中在1-2微米和3-10微米波段，而2-3微米波段很少研究，该波段覆盖了众多工业排放和人体呼吸气体分子的基频吸收峰，在环境监测、医学诊断等领域有重要应用。本课题基于GaSbBi材料的宽光谱特性且室温发光波长覆盖2-3微米特点，原创性提出用稀铋材料实现宽调谐范围外腔激光器。以研制2-3微米宽调谐GaSbBi量子阱外腔激光器为目标，创新设计四种宽增益谱GaSbBi量子阱激光器结构，采用分子束外延技术生长激光器材料，研究生长条件对材料结构、电学和光学特性的影响，优化生长条件，探索器件制备工艺，实现高性能宽增益谱GaSbBi量子阱激光器，搭建和测试可调谐外腔激光器，研究稀铋量子阱外腔激光器的调谐机制，演示调谐范围>200nm，单模输出功率>10mW，边模抑制比>30dB的2-3微米波段连续调谐外腔激光器。

稀铋化合物因铋原子的凝入而具有带隙收缩、自旋轨道分裂能增大等特性，GaSbBi材料体系有望实现在中红外波段的室温激光器，在中红外波段具有潜在应用价值。另外，InAs/GaSb/InSb超晶格结构，可以通过改变InAs层和GaSb层厚度，实现在中红外波段以及更长波长的光致发光，因此具有重要的研究意义。本项目主要针对这两种材料结构的分子束外延生长规律和光致发光规律展开研究讨论。系统地研究了生长温度、V/III 族束流比等生长参数对GaSbBi量子阱的铋原子凝入和材料光致发光的影响；研究了不同delta掺杂浓度对GaSbBi量子阱带隙的影响, 并对比了室温下有delta掺杂和未掺杂的发光波长与发光效率，验证了delta掺杂可以拓展发光波长；研究了InAs/GaSb/InSb 超晶格的生长规律，分析讨论了不同砷、锑压对材料界面的影响和发光强度的影响，验证了可以通过掺入铋原子拓展超晶格的发光波长，并且研究了铋原子对超晶格发光的影响。