Zhou Yi, Tang Yan, Zhu Jiangping, Deng Qinyuan, Yang Yong, Zhao Lixin, Hu Song
Appl Opt. 2017 Mar 10;56(8):2301-2306. doi: 10.1364/AO.56.002301.
Broadband light interferometry, which is a well-developed method for surface profiling, has been applied with great success in the past years. Conventional multi-wavelength interferometric surface profilers mostly utilize the light irradiance to locate the zero fringe order, but the accuracy and stability can be negatively influenced by intensity fluctuations and external light disturbance, which is a serious problem. In this paper we discuss a hybrid technique combining light intensity and spectral modulation to determine zero optical path difference in which the light instability can be effectively suppressed. Additionally, the phase evaluation at each pixel will provide a high vertical resolution to obtain the characterization of the micro structure. The hybrid-interference method will not only improve the sensitivity of the measurement system but also level up the robustness and stability. Both simulation and experiment on a micro-dome structure have been presented to verify the effectiveness. Furthermore, the proposed method may be promising to replace the previously intensity-based method, especially in a complex application environment.
宽带光干涉测量法是一种成熟的表面轮廓测量方法，在过去几年中得到了广泛应用。传统的多波长干涉表面轮廓仪大多利用光辐照度来确定零条纹级次，但强度波动和外部光干扰会对测量的准确性和稳定性产生负面影响，这是一个严重问题。在本文中，我们讨论了一种结合光强和光谱调制来确定零光程差的混合技术，该技术可以有效抑制光的不稳定性。此外，每个像素处的相位评估将提供高垂直分辨率，以获得微观结构的特征。这种混合干涉方法不仅会提高测量系统的灵敏度，还会提升其鲁棒性和稳定性。我们给出了在微穹顶结构上的仿真和实验结果，以验证该方法的有效性。此外，该方法有望取代以前基于强度的方法，特别是在复杂的应用环境中。
