We study the facet temperature distribution of a high-power diode laser over its lifetime using a noncontact, high spatial resolution CCD-based thermoreflectance technique. Based on the known correlation between non-radiative defects and heating, thermal maps can provide valuable information regarding the formation and evolution of small point defects that are at or near the facet during aging. In the laser under study in this work we measure the appearance of local hot spots on the facet, including concentrated hot spots that appear just before or just after COD and are correlated with loss of local light emission. The locations of these hot spots do not exhibit morphology changes in high-resolution SEM imaging of the facet, indicating that the related defects are too small to be observable in SEM or are located at some depth under the facet. Prior to COD, we measure a gradual facet temperature increase accompanied by a gradual optical power decrease and gradual facet optical absorption increase, indicating gradual degradation of the laser.

中文翻译：

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高功率二极管激光端面老化过程中的高分辨率热分析

我们使用基于 CCD 的非接触式高空间分辨率热反射技术研究高功率二极管激光器在其使用寿命期间的端面温度分布。基于非辐射缺陷和加热之间已知的相关性，热图可以提供有关老化过程中刻面处或刻面附近的小点缺陷的形成和演变的有价值的信息。在这项工作中研究的激光器中，我们测量了刻面上局部热点的出现，包括在 COD 之前或之后出现的集中热点，这些热点与局部光发射的损失相关。这些热点的位置在刻面的高分辨率 SEM 成像中没有表现出形态变化，表明相关缺陷太小而无法在 SEM 中观察到，或者位于刻面下方的某个深度。在 COD 之前，我们测量了小面温度逐渐升高，同时光功率逐渐降低，小面光吸收逐渐增加，这表明激光器逐渐退化。