近日，國際Optica出版集團Spotlight亮點專欄報道理學院吳真副教授在外腔反饋半導體激光陣列穩(wěn)定性條件方面的最新研究進展。相關研究發(fā)表在光學領域權威期刊《Journal of the Optical Society of America B-optical Physics》上，論文題目：Dynamics and stability conditions of a spectrally combined beam based on a diode laser array

吳真副教授為通訊作者，四川大學電子信息學院鐘哲強副教授為合作者，西華大學為第一通訊單位，2022級碩士研究生馮鵬為第一作者，2023級碩士研究生李丹妮為第二作者。

隨著半導體激光在材料加工、激光雷達和光學成像等領域的不斷發(fā)展，對半導體激光器的輸出功率和光束質量提出了很高的要求。然而，由于熱效應和非線性效應，半導體激光器的光束質量通常會隨著功率的增加而惡化。如何獲得兼具高功率和高光束質量的半導體激光源成為國際上亟待解決的問題。譜合束技術由于不需要精確控制相位和偏振而得到廣泛的研究，該技術采用外腔反饋結構鎖定子束光譜實現(xiàn)能量疊加。然而，外部光反饋以及串擾效應有可能引起這些激光器的混沌行為。混沌效應可能導致激光器相干坍縮、光譜展寬和效率降低等問題，并且混沌激光的輸出表現(xiàn)出高度不規(guī)則和不可預測的特性，極大地限制了半導體激光源的應用。該論文采用四階龍格庫塔法求解半導體速率方程，并引入一個穩(wěn)定性條件評價光反饋半導體激光器的潛在特性。穩(wěn)定性條件可以計算和預估光束的輸出狀態(tài)。基于穩(wěn)定性條件，分析了外腔參數對反饋因子的影響。該工作為實現(xiàn)高亮度半導體激光穩(wěn)定光源的應用奠定了基礎。

文章鏈接：https://doi.org/10.1364/JOSAB.514043

Spotlight專欄評價道：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.