Optica出版集团Spotlight亮点专栏报道理学院教师最新研究进展

近日，国际Optica出版集团Spotlight亮点专栏报道理学院吴真副教授在外腔反馈半导体激光阵列稳定性条件方面的最新研究进展。相关研究发表在光学领域权威期刊《Journal of the Optical Society of America B-optical Physics》上，论文题目：Dynamics and stability conditions of a spectrally combined beam based on a diode laser array

吴真副教授为通讯作者，四川大学电子信息学院钟哲强副教授为合作者，西华大学为第一通讯单位，2022级硕士研究生冯鹏为第一作者，2023级硕士研究生李丹妮为第二作者。

随着半导体激光在材料加工、激光雷达和光学成像等领域的不断发展，对半导体激光器的输出功率和光束质量提出了很高的要求。然而，由于热效应和非线性效应，半导体激光器的光束质量通常会随着功率的增加而恶化。如何获得兼具高功率和高光束质量的半导体激光源成为国际上亟待解决的问题。谱合束技术由于不需要精确控制相位和偏振而得到广泛的研究，该技术采用外腔反馈结构锁定子束光谱实现能量叠加。然而，外部光反馈以及串扰效应有可能引起这些激光器的混沌行为。混沌效应可能导致激光器相干坍缩、光谱展宽和效率降低等问题，并且混沌激光的输出表现出高度不规则和不可预测的特性，极大地限制了半导体激光源的应用。该论文采用四阶龙格库塔法求解半导体速率方程，并引入一个稳定性条件评价光反馈半导体激光器的潜在特性。稳定性条件可以计算和预估光束的输出状态。基于稳定性条件，分析了外腔参数对反馈因子的影响。该工作为实现高亮度半导体激光稳定光源的应用奠定了基础。

文章链接：https://doi.org/10.1364/JOSAB.514043

Spotlight专栏评价道：A key challenge in designing a spectral beam combining (SBC) system based on a diode laser array (DLA) is how to avoid excessive optical feedback induced by the diffraction grating in the system. Optical feedback introduced into individual laser elements in the array may cause unwanted instabilities in the lasers’ output, leading to poor beam quality. To tackle this challenge, the authors of this paper explore theoretically the impact of optical feedback in the DLA-based SBC system using, where possible, experimental parameters. The results show that the diversity of dynamics available from the lasers is high and their output follows a well-defined route to deterministically chaotic output. Further analysis gives the stability region described by the key system parameters including feedback factor, focal length of the transform lens, reflectivity of the output coupler and the reflectivity of the front facet of the diode laser. The findings presented in this paper provide practical guidelines for the design of a high brightness and good beam quality DLA-based SBC system.