基于介质模的金属限制半导体纳米激光器的物理极限尺寸研究

Micro/nano lasers are key devices in photonic integrated circuits. By reducing their sizes, the integration density of devices can be increased and the power consumption can be decreased. Thus minimization of laser sizes has been a long pursuing goal. Nanolasers based on surface plasmon polaritons (SPP) of metallic structures have the capability of confining optical field at deep subwavelength scales. However, SPP lasers have relatively high threshold due to high absorption losses of metals. This project will study metal confined semiconductor nanolasers with dielectric modes, analyzing and testing the physical size limit of such type of lasers which will work at room temperature. In order to enhance the confinement of optical field by the nanocavity and decrease the threshold of lasers, the effect of metallic layer and dielectric insulating layer on the mode distributions and Q factor of semiconductor nanocavity will be investigated. And the effects of laser size on the resonant wavelengths, optical confinement factors and Q factors of different modes will be studied. Suitable nanocavity mode will be chose and the size limit of nanolasers which can work at room temperature will be analyzed. Furthermore, the effect of electrodes on the field distributions and Q factors of modes will be studied and the physical parameters of lasers will be optimized. This project will design and fabricate prototypes of metal confined semiconductor nanolasers with sizes of physical limit. The lasers will be pumped electrically and work at room temperature. This project will significantly promote the development and applications of semiconductor nanolasers.

微纳激光器是光子集成回路的核心器件，通过缩小尺寸可以提高器件的集成密度并降低功耗，因此最大限度缩小激光器的尺寸是人们追寻的目标。基于金属表面等离激元共振（SPP）效应的纳米激光器可以将光场局域在深亚波长尺度，但金属吸收损耗大，SPP激光器的阈值相对较高。本项目以基于介质模的金属限制半导体纳米激光器为研究对象，分析和验证能在室温工作的该类激光器的物理极限尺寸。项目将研究金属层和绝缘层对半导体纳腔模式的模场分布与Q值的影响，以增强纳腔对光场的约束，降低激光器的阈值；研究不同模式的共振波长、光限制因子与Q值等随激光器尺寸的变化关系，合理选择纳腔模式，分析能在室温工作的纳腔激光器的极限尺寸；研究电极的引入对模场和Q值的影响，优化激光器的物理参数。项目将设计和制备出具有极限尺寸的金属限制半导体纳米激光器原型器件，使激光器在电注入下实现室温激射，有力推动半导体纳米激光器的深入发展与应用。

本项目以基于介质模的金属限制半导体纳米激光器为研究对象，系统研究该类激光器的模式特性以及能在室温工作的该类激光器的物理极限尺寸。项目研究了激光器中金属层和介质隔离层对半导体纳腔模式的影响，分析了不同金属材料对腔模Q值的影响，分析了金属层与介质层厚度对腔模Q值与波长的影响并对金属和介质层厚度进行了优化；项目系统分析了纳米激光器中最低阶介质模附近的几阶模式，综合考虑模式的 Q 值与光限制因子等，分析得出了能在室温工作的纳米激光器的极限尺寸；项目研究了半导体纳米激光器的制备工艺，实验研制出不同尺寸的圆形半导体纳米激光器，并利用红外相机直接观测到圆形纳米激光器中的单极子、偶极子以及四级子等激射模式（波长在1.5微米附近）；项目研制出波长尺度方形半导体激光器，其边长为2.2微米，激射模式的波长为1556.5 nm，线宽为0.27 nm，边摸抑制比为21 dB；项目研制出超短F-P腔半导体激光器，其腔长约7微米，激射模式的波长为1556 nm，线宽为0.06 nm，边摸抑制比为30 dB。总之，本青年自然科学基金项目系统研究了基于介质模的金属限制半导体纳米激光器的模式特性与物理极限尺寸，并实验研制出室温工作的亚波长圆形半导体纳米激光器以及具有波长量级尺寸的半导体方形激光器与F-P腔激光器。项目资助发表SCI学术论文16篇，待发表2篇；培养本科毕业设计5人，培养硕士研究生1人。