Analysis of Fraunhofer diffractive characteristics of a tilted metallic mesh for its effect on optical measurement

作者：Tan Jiubin^*; Lu Zhengang; Liu Jian; Jin Peng; Wang Yanchao

来源：Measurement Science and Technology, 2007, 18(6): 1703-1709.

DOI：10.1088/0957-0233/18/6/S06

• optical imaging
• Fraunhofer diffractive characteristics
• tilted metallic mesh diffraction
• slot width measurement

In order to analyse the Fraunhofer diffractive characteristics of a tilted metallic mesh for its effect on optical measurement, a model is built for Fraunhofer diffraction optical intensity distribution using Huygens - Fresnel diffraction theory; a stretch factor is introduced to represent the stretching of diffraction spots along axis x, as a result of variation in the effective area of a clear aperture after mesh tilting, and an offset factor is introduced to represent the asymmetrical distribution of diffraction spots caused by mesh tilting and the distance between the centre of zero-order diffraction and the observation point. The diffraction characteristics of the tilted mesh are in good agreement with experimental results, which proves the correctness of the model established for it. The location of the centre of zero-order diffraction does not change with theta in an aerial optical measurement, and an increase by 1/ cos(theta) times its primary maximum radius along axis x due to the prevailing stretch factor causes a decrease in the resolution of an optical system by the same magnitude. The model established for a tilted mesh can also be used to remove any error due to a tilted slot during slot width measurement.

• 出版日期2007-6
• 单位哈尔滨工业大学