拓扑保护连续束缚光子态新光场调控机理与高性能激光研究

One of the bottlenecks of semiconductor laser is how to realize single-mode and meanwhile with high-power output. Intrinsically, a large mode volume is needed to achieve high power output, and the large volume of the mode will inevitably lead to multimode effect. The inherent contradictions have plagued scientists such a long time that the single mode laser output is only achieved by sacrificing output power currently. The improvement of semiconductor laser performance based on the manipulation of photon states has been fully verified in photonic crystal lasers. This project aims to find new regulatory mechanisms and achieve single-mode high-power laser output. The photonic bound state in the continuum (BIC) found in photonic crystals in recent years has aroused people's interest in research. Its theoretical and experimental research has just started. However, the research on the high efficiency energy output for such strong photonic BIC is empty, especially on the field of application to single mode high power lasers. This project will study in depth the photonic BIC and topological protection mechanisms in photonic crystals. Through the coupling of the complex cavities, the loss induced new parity-time (PT) phase transition mechanism will be studied to explore new principles of how the strongly confined photon states in semiconductor lasers can achieve high energy output. The project involves a new type of photonic BIC in non-Hermitian optical systems. The research results can not only deepen and enrich the understanding of photonic BIC formation mechanisms, but also help us to develop new technologies for high-performance laser. In conclusion, such project is very important and quite meaningful not only in science but also in the potential applications.

如何实现单模高功率激光输出是目前半导体激光亟待解决的瓶颈问题。本质上实现高功率输出需要大模式体积，模式体积大必然产生多模，这对本征矛盾一直困扰着科学家们，目前的单模输出都是通过牺牲功率而实现的。基于调控光子态提高半导体激光性能在光子晶体激光中已经得到充分验证，本项目旨在寻找新调控机制，实现单模高功率激光输出。近几年在光子晶体中发现光子连续束缚态（BIC），引起了人们的关注，其理论与实验研究刚刚起步，而强约束光子BIC的高效能量输出目前是研究空白。本项目将深入研究光子晶体中光子BIC及拓扑保护机制，通过复合腔耦合，研究损耗诱导新型宇称-时间（PT）相变机制，探索半导体激光中强约束光子态实现高能量输出的新原理。项目中所涉及的是非厄米光学系统中的新型光子BIC，研究成果不仅可以加深和丰富对光子BIC形成机制的认识，具有重要的科学意义，而且可以探索实现高性能激光新技术，具有重要的潜在应用价值。

半导体激光已成为激光应用及技术领域的核心光源，带动了世界范围的千万亿产值新技术领域的发展。在此重大应用需求牵引的推动下，高性能半导体激光如单模高功率激光的发展，成为科学界和产业界联合攻关的重要方向。输出高功率激光需要激光模式体积大，而模式体积大必然带来模式数目多的问题。通过完成本项目，找到了新模态调控机制，克服了瓶颈问题，实现了高性能激光输出。.项目严格按计划执行，完成情况良好，取得的关键成果如下：.1.发现了光子晶体K空间沿Γ-X的任意位置操控merging-BIC的规律，实现了具有低阈值电流密度和高输出功率的电注入光子晶体复合腔BIC激光器，阈值电流密度829 A/cm2，偶然BIC单模激射功率~3.03 mW@400 mA；.2.实现对PT对称激光器的奇异点（EP）相对于激射阈值的位置进行了调控，EP位于激射阈值之上（下）时在大（小）电流下具有单瓣远场；.3.提出沿侧向引入宇称-时间对称诱导的非厄密相变调控激光模场，构建了非厄密拓扑在提升激光器性能鲁棒性研究的新维度；.4.将粒子物理的超对称原理映射至半导体激光器的外延结构设计中，提出了一种基于超对称外延的低垂直发散角半导体激光器研究的新思路，有效降低垂直发散角至<17°；.5.研制了高亮度、高功率密度横向光子晶体复合腔激光器，获得二阶矩水平最高亮度126.8 MW/(cm2 ·sr)，在量子阱的位置偏离光子晶体缺陷层中光场最强位置时，最大输出功率在连续电流48A@5℃下达到41.8 W，为目前报道单管功率最高结果，电光转换效率最大为64.7%，48A下远场发散角半高全宽为16.5°×16.8°；.6.基于无高温焊接技术的光子晶体激光阵列，焊接应力降低18.6倍，峰值功率高达292.2W，峰功率密度为传统半导体激光巴条的1.75倍。.项目发表SCI论文54篇，授权专利15项，新申请专利15项，培养博士、硕士研究生17名，部分成果已投产应用。所研制的新型电注入激光器，结合了凝聚态物理与半导体人工微结构的模态调控新方法，不仅拓展了半导体激光物理的研究范畴，同时有效优化了激光器的性能，这种交叉研究正成为目前半导体激光科学研究的热点。