光学 精密工程, 2014, 22 (1): 69, 网络出版: 2014-02-18
基于受抑全反射的碱金属气室镀膜厚度测量
Accurate measurement of coating thickness for alkali vapor cells based on frustrated total internal reflection
碱金属气室 受抑全反射 膜厚测量 激光测量法 alkali vapor cell Frustrated Total Internal Reflection(FTIR) coating thickness measurement laser measuring method
摘要
针对原子自旋器件的碱金属气室镀膜层厚度的精确测量,提出了一种基于受抑全反射的膜层厚度测量方法。根据该方法搭建了膜厚测量系统,并进行了实验测试。分析了受抑全反射的基本理论和基于受抑全反射的膜厚测量原理,介绍了基于该方法的膜厚测量系统的构成及工作原理并分析了影响系统测量精度的主要因素和解决方案。通过分析和仿真激光器波长的波动、入射角变化以及折射率参数的不准确等对膜厚测量结果的影响评价了系统的性能。最后,利用该系统对镀膜样品进行了测量实验,并利用薄膜分析仪做了对比试验。实验结果表明: 该方法的测量结果存在一个2.6 nm左右的常值偏差,对其补偿后能够较为准确地对镀膜层厚度进行测量,测量精度接近1 nm,基本满足碱金属气室镀膜质量检测的需求,且具有较高的稳定性和可靠性。
Abstract
For the accurate measurement of coating thicknesses for alkali vapor cells in atomic spinning devices, a measurement method based on Frustrated Total Internal Reflection (FTIR) was proposed. A coating thickness measuring system was established and experimental tests were performed. The phenomenon of FTIR and the principle of coating thickness measurement based on the FTIR were analyzed. And the main factors impacting the measuring accuracy of the system were analyzed and several solutions were given. Furthermore, the performance of the system was evaluated by analyzing and simulating the effects of the wavelength fluctuation, change of laser incident angle, and other inaccurate refractive indexes on the measured results. Finally, the thickness measuring experiment using the system and a check experiment using a film analyzer were carried out for the coating sample. Experimental results indicate that data from the FTIR system generally have a deviation about 2.6 nm. But the system can measure coating thickness exactly with a precision about 1 nm after the deviation compensated, which can satisfy the requirement of evaluation of coating qualities for alkali vapor cells under high stability and reliability.
全伟, 刘阳, 陈瑶. 基于受抑全反射的碱金属气室镀膜厚度测量[J]. 光学 精密工程, 2014, 22(1): 69. QUAN Wei, LIU Yang, CHEN Yao. Accurate measurement of coating thickness for alkali vapor cells based on frustrated total internal reflection[J]. Optics and Precision Engineering, 2014, 22(1): 69.