焦点移动现象的规律及成因  

The Rule of the Phenomenon of Focal Point Shift and the Cause of its Formation

作　　者：让庆澜[1] 

机构地区：[1]北京大学物理系,北京100871

出　　处：《应用激光》1999年第1期15-18,共4页Applied Laser

摘　　要：指出高斯光束人射时国孔衍射场的一般规律．画了不同Nw时衍射场振幅随（H，Pm）变化的函数图形。找到振幅极大值点移动的原因及焦移量的计算公式．The general rule of the diffraction field U(P) at a circular aperture illuminated by a Gaussian beam is given. The diagram of | U (p) | as a function of (H, Pm) are drawn for different Nw. The cause for the focal point shift is given. A formula for calculation of the amount of the focal point shift is given as well.

关 键 词：球面波 高斯光束 圆孔衍射 焦点移动 

分 类 号：O436.1[机械工程—光学工程]