基于太赫兹时域光谱技术的多层涂层高效可靠测厚方法  

Efficient and Reliable Thickness Measurement Method for Multilayer Coatings Based on Terahertz Time-Domain Spectroscopy Technology

作　　者：曹丙花 郑德栋 范孟豹[2] 孙凤山 刘林 Cao Binghua;Zheng Dedong;Fan Mengbao;Sun Fengshan;Liu Lin(School of Information and Control Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221000,China;School of Mechatronic Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221000,China;Beijing Institute of Aerospace Metrology and Measurement Technology,Beijing 100076,China)

机构地区：[1]中国矿业大学信息与控制工程学院,江苏徐州221000 [2]中国矿业大学机电工程学院,江苏徐州221000 [3]北京航天计量测试技术研究所,北京100076

出　　处：《光学学报》2022年第1期119-129,共11页Acta Optica Sinica

基　　金：国家自然科学基金(62071471)。

摘　　要：为实现基于太赫兹技术的多层涂层的快速与可靠测厚,提出了一种自适应教与学优化算法,改进了标准Kent混沌映射,提高了初始种群多样性;并基于步长调节优化和次优个体优化,改进了教阶段与学阶段,提高算法寻优精度和效率。将该算法与太赫兹波测量多层涂层厚度的理论模型结合,建立了涂层厚度求解方法。最后,制备了多层涂层样件,开展了太赫兹无损检测实验。实验结果表明:建立的涂层厚度求解方法相比于全局最优算法的效率提高了1倍,单次实验仅需50 s左右便可快速得到多层涂层的厚度、折射率和消光系数,测量所得的多层涂层厚度的相对误差在1.5%以内,且标准差最大不超过1.7μm。基于太赫兹测量信号,所提方法可以高效、准确及可靠地计算多层涂层的厚度。To realize a fast and reliable thickness measurement of multilayer coatings based on terahertz technology, an adaptive teaching-learning-based optimization algorithm was proposed. In this algorithm, the standard Kent chaotic mapping was improved to increase the initial population diversity. Moreover, the teaching and learning phases were enhanced based on step adjustment optimization and suboptimal individual optimization to achieve improved optimization accuracy and efficiency of algorithm. Then, the proposed algorithm was combined with a theoretical model for measuring multilayer sample thicknesses with terahertz waves. A method for determining the thickness of the coatings was developed. Finally, multilayer coatings were prepared and terahertz nondestructive testing experiments were performed. Results show that the efficiency of the proposed method is twice that of the global optimal algorithm. The thickness, refractive index, and extinction coefficient of the multilayer coatings can be obtained quickly in a single measurement in only ~50 s. The relative error of the measured multilayer coating thickness is within 1.5%, and the maximum standard deviation is no more than 1.7 μm. Based on the terahertz measurement signal, the proposed method can be used to efficiently, accurately, and reliably determine the thickness of multilayer coatings.

关 键 词：测量 太赫兹 厚度测量 多层涂层 教与学优化算法 理论模型 

分 类 号：O433.4[机械工程—光学工程] TB96[理学—光学]