摘要
夫朗和费衍射常用来测量微小尺寸，实验表明，衍射角较大时，存在较大的系统误差，测量结果不能正确反映被测量大小。本文以狭缝为例，采取一种新的近似处理方法，导出了较为准确的测量公式，分析了测量的正确度问题，指出夫朗和费近似只是必要条件，而要获得正确的测量结果，最大衍射角必须在一定范围内。同时，这种方法也不能测量任意微小尺寸，最小可测尺寸与所要求的正确度有关，要求的正确度越高，最小可测尺寸越大。上述结论同样适用于刻划光栅、金属丝网、徐层厚度及其它狭缝类或圆孔类物体的衍射测量。
Fraunhofer diffraction is often used to measure the dimensions of small objects.It isfound that when the diffraction angle is large there is a serious systematic error,the result has large de-viation from real dimension,Taking slit diffraction under Fraunhofer approximation as an example,thearticle has derived a more accurate formula for the measurement and analyzed the correctness of the nor-mally used measurement formula,It shows that the Fraunhofer approximation is only a necessary condi-tion,In order to get correct measurement,the largest diffraction angle must be at finite range undercertain correctness,and the method can not be used to measure too small objects,the minimum mea-sureable dimension (MMD)is closely related to the correctness required,and the higher the correctnessrequired,the larger the MMD. This conclusion is also useful to the diffraction measurement of rulinggrating,or thogonal metal net,coating thickness and circular hole and so on.
出处
《光学技术》
CAS
CSCD
1995年第2期36-39,共4页
Optical Technique
关键词
衍射
测量
系统误差
夫朗和费近似
夫郎和费衍射
diffraction,measurement,correctness,systematic error,Fraunhofer approximation
