厄米双曲余弦高斯光束的焦开关  

Focal switch effect of Hermite-cosh-Gaussian beams

作　　者：黄太星[1] 季小玲[1] 

机构地区：[1]四川师范大学电子工程学院,四川成都610066

出　　处：《光电工程》2006年第2期54-57,共4页Opto-Electronic Engineering

基　　金：四川省教育厅自然科学基金资助项目(2002A089)

摘　　要：对双曲余弦高斯光束通过光阑透镜分离系统的轴上光强分布做了详细的数值分析。研究发现,在一定条件下轴上存在两个光强极大值点,并且在这两个极大值点相互竞争中会出现焦点位置的有效置换,即出现焦开关。厄米双曲余弦高斯光束产生焦开关的条件是:光阑与透镜相对间距为1,光束阶数为偶数,光束参数小于其相应的临界值,截断参数在它的两个临界值之间。进一步研究表明,焦点位置相对跃迁量和轴上相对光强下凹量随光束参数的减小而增大,但是随着截断参数的增大焦点位置相对跃迁量和轴上相对光强下凹量将分别出现一个极大值。在大范围调焦的应用中,可利用焦开关实现调焦之目的;在精密聚焦的激光应用中,应控制焦开关的产生。The axial intensity distribution of Hermite-cosh-Gaussian （HChG） beams passing through a system with the aperture and lens separated is studied numerically. It is found that, under certain conditions there exist two intensity maxima along the axis, and an effective permutation of the focal point can take place due to the competition between the two maxima, i.e., focal switch appears. For HChG beams the conditions of focal switch are that the relative separation of the aperture and lens is 1, the beam order is even, the beam parameter is smaller than its corresponding critical value, and the truncation parameter is between its two corresponding critical values. Furthermore, it is shown that the relative transition height and the relative intensity sunken height increase with decreasing the beam parameter, but as the truncation parameter increases there exists a maximum of the relative transition height and the relative intensity sunken height＇ respectively. The focal switch can be used to focus within a large range, but the focal switch should be avoided in precision focus.

关 键 词：厄米双曲余弦高斯光束 光阑一透镜系统 焦开关 焦移 

分 类 号：O435[机械工程—光学工程]