The interference contrast in a near-field diffraction pattern can be improved using an asymmetric grating with a small grating window. However, commercial asymmetrically shaped gratings are not available. Here, we report a method that overlaps two gratings to produce an arbitrary open fraction in the combination grating. Both theoretical simulation and experimental observations of the near-field Talbot effect are provided to validate this concept. A characterization of optical vortices is also used as a demonstration of potential applications. This method is simple and can improve the resolution in metrology with optical sensors.

中文翻译：

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生成具有所需开放分数的一维周期性强度轮廓的简单技术，适用于光学传感器应用

使用具有小光栅窗口的不对称光栅可以改善近场衍射图中的干涉对比度。但是，没有商用的不对称形状的光栅。在这里，我们报告了一种将两个光栅重叠以在组合光栅中产生任意开口率的方法。理论仿真和近场Talbot效应的实验观察都可以验证这一概念。光学涡旋的表征也被用作潜在应用的演示。这种方法很简单，可以提高光学传感器的计量分辨率。