Zhu Xianchang, Hu Song, Zhao Lixin
Appl Opt. 2014 Oct 10;53(29):6663-9. doi: 10.1364/AO.53.006663.
Based on grating shearing interferometry, a simple technique is introduced for focal length measurements of a microlens-array (MLA). The measurement system is composed of a He-Ne laser, condenser, collimator, the MLA under testing, a Ronchi grating, and CCD sensor. The plane wavefront from the collimator is transformed to a spherical wavefront by the MLA, while the curvature center is at the focus. Interference stripes appear at the overlap between the zero-order and first-order diffractive patterns of the grating and are detected by the CCD sensor. By analyzing the period change of stripes, the focal length is determined after the defocus of the grating is calculated. To validate the feasibility, an experiment is performed. The measurement uncertainty is discussed and measurement accuracy was determined to be 2%.
基于光栅剪切干涉测量法，介绍了一种用于微透镜阵列（MLA）焦距测量的简单技术。测量系统由氦氖激光器、聚光镜、准直仪、待测微透镜阵列、罗恩奇光栅和电荷耦合器件（CCD）传感器组成。准直仪发出的平面波前被微透镜阵列转换为球面波前，其曲率中心位于焦点处。干涉条纹出现在光栅零级和一级衍射图样的重叠处，并由CCD传感器检测到。通过分析条纹的周期变化，在计算出光栅离焦量后确定焦距。为验证该方法的可行性，进行了实验。讨论了测量不确定度，确定测量精度为2%。
