设计了一套迈克耳孙白光干涉仪系统用于测量光学薄膜的反射相位,并由此反推单层薄膜的物理厚度。为补偿传统算法获取相位所存在的误差,提出一种新算法,以线性拟合结果作为初始猜想,采用多变量优化拟合总光程差曲线得到光学薄膜的相位。通过数值模拟的方式论证了理论上的可行性和高计算精度。采用多变量优化的手段进行处理实际测试的一组单层TiO2薄膜,所得物理厚度值与传统的光度法测试反演结果非常吻合。该测试系统和处理算法为快速精确测量光学薄膜厚度提供了一种新的解决方案。

White-light spectral interferometer for measuring physical thickness and reflection phase of thin film is designed. A novel algorithm is also presented to compensate the phase retrieval error in traditional signal processing method. Exact reflection phase is retrieved via a multiple variable optimization algorithm,and the result of linear fit is used as the initial guess. Numerical simulation is performed to demonstrate theoretical availability and high precision of the algorithm. A group of single layer TiO2 thin films are measured and processed with this method,and the retrieved physical thickness results fit the results by photometry very well. The system and algorithm presented provide a new way for fast measurement of thin film thickness.