Huang Liangjin, Guo Shaofeng, Leng Jinyong, Lü Haibin, Zhou Pu, Cheng Xiang'ai
Opt Express. 2015 Feb 23;23(4):4620-9. doi: 10.1364/OE.23.004620.
Today a specific attention has been paid to look into the modal characteristics of the high-power laser beam. And the instantaneous monitoring and analyzing on modal content via the mode decomposition technique will provide a novel route. We implement the first-ever experimental investigation on the real-time mode decomposition technique for few-mode laser beam based on stochastic parallel gradient descent algorithm. It will reduce the cost and the complexity of the mode decomposition system. We have succeeded to decompose the mode spectra as well as calculating the beam quality factor at about 9 Hz monitoring rate, while the high agreement between the measured and reconstructed intensity profiles in each frame indicating the high accuracy and stability during the process. By employing a fiber-squeezing-based polarization controller, the modal content under test can be time-varying automatically.
如今，人们已特别关注研究高功率激光束的模态特性。通过模式分解技术对模态内容进行实时监测和分析将提供一条新途径。我们基于随机并行梯度下降算法，首次对少模激光束的实时模式分解技术进行了实验研究。这将降低模式分解系统的成本和复杂性。我们已成功在约9Hz的监测速率下分解模式光谱并计算光束质量因子，同时每一帧中测量强度分布与重建强度分布之间的高度一致性表明该过程具有高精度和稳定性。通过采用基于光纤挤压的偏振控制器，被测模态内容可自动随时间变化。
