EchSGB远距离照明条件下的焦开关  

Focal Switch of EchSGB Illumination at Long Range

作　　者：郝中骐[1] 朱开成[1] 文伟[1] 

机构地区：[1]中南大学物理科学与技术学院,长沙410083

出　　处：《光学与光电技术》2007年第4期12-15,共4页Optics & Optoelectronic Technology

摘　　要：推导了复变量双曲余弦平方-高斯光束(EchSGB)被无光阑透镜聚焦后的轴上光强分布公式,在此基础上通过数值计算和分析发现,EchSGB只有在远距离照明条件下才存在焦开关现象。焦点跃变位置随光束参数和对应高斯光束的菲涅尔数不同而变化,得到了EchSGB在平顶情形下产生焦开关的相对入射距离为11.13,表明在远距离照明和无光阑透镜精密调焦时,对于EchSGB要考虑焦开关现象的影响。The complex variable cosh-squared-Gaussian beams（EchSGB） is focalized by the lens without stop. The light intensity distribution formula at the axis is derived. On the basis, it is found that the focal switch effect occurs only on the condition of long range illumination through numerical calculation and analysis. The focal transition position is changed with the different beams parameters and Fresnel numbers corresponding to Ganssian beams. For the flattened EchSGB, the relative distance of the focal switch producing is 11.13. The results show that the effect of focal switch should be considered with short focal length and precision focusing under the condition of long-range illumination.

关 键 词：复变量双曲余弦平方-高斯光束 无光阑透镜 焦移 焦开关 

分 类 号：O435[机械工程—光学工程]