摘要
提出了一种测量凹透镜焦距的方法。这种测量方法基于光栅的弗朗和费衍射,无需测量物距和像距。钠光通过一个狭缝和一个凸透镜后变成一束平行光;平行光垂直入射光栅后被衍射;利用已知焦距的长焦距凸透镜确定凹透镜成像的像位置;利用已知焦距的短焦距凸透镜确定凹透镜成像的物位置;衍射光通过一个凸透镜和待测凹透镜后形成衍射条纹;这些衍射条纹被测微目镜测量。只要测量衍射条纹的间距就可计算得到凹透镜的焦距。
In this paper,we present a method to measure the focal length of concave lens.The meas-urement method is based on the Fraunhofer diffraction of grating,and does not need to measure the ob-ject and image distances.Sodium light becomes a beam of parallel light after passing through a slit and a convex lens.The parallel light enters the grating vertically and then is diffracted.A long focal length convex lens of known focal length is used to determine the image position of the concave lens imaging.A short focal length convex lens with known focal length is used to determine the object position of the concave lens imaging.The diffraction fringes are formed after the diffracted light passes through a con-vex lens and a concave lens.The diffraction fringes are measured by a micro-eyepiece.The focal length of concave lens can be calculated by measuring the distance between the diffraction fringes.
作者
翁存程
陈悦华
何友武
WENG Cuncheng;CHEN Yuehua;HE Youwu(College of Physics and Energy,Fujian Normal University,Fuzhou 350007,China;College of Photonic and Electronic Engineering,Fujian Normal University,Fuzhou 350007,China)
出处
《实验室科学》
2021年第2期1-2,6,共3页
Laboratory Science
基金
福建省自然科学基金(项目编号:2019J01268)
福建师范大学教改项目(项目编号:I202002090)。
关键词
凹透镜
焦距
弗朗和费衍射
concave lens
focal length
Fraunhofer diffraction
