湍流大气对高斯光束聚焦特性的影响

基于广义惠更斯-菲涅尔原理,推导出高斯光束在湍流大气中经薄透镜聚焦后的光强解析表达式,进而得到轴上点最大光强和相对焦移的公式。对表达式进行的数值仿真结果表明,湍流大气中高斯光束的聚焦规律与自由空间中高斯光束的聚焦规律相同,湍流大气对高斯光束聚焦特性的影响表现为,使得轴上点最大光强减小、相对焦移增大。因此,为在探测器上获得最大光强和较小的相对焦移,应采用大束腰高斯光束通过短焦距透镜进行聚焦。

Influence of turbulent atmosphere on the focusing properties of Guassian beam

Based on the generalized Huygens-Fresnel integral,analytical propag ation formulas for Guassian beams through thin lenses in turbulent atmosphere are derived,and the expressions of on-axis maximum intensi ty on-axis and relative focal shift are evaluated by the propagation formulas.The expression are studied numerically,and the results show tha t the law of focus properties in turbulent atmosphere is the same as that in free space.In other words,the relative focal shift of Gussian beam firstly increases to a maximum value and then decreases gradually with the increasing of the propagation distance,it is reduced with the increasing of the beam waist,and the greater the focal length of thin lenses is, the greater the relative focal shift is.The influence of turbulent atmospher e on focusing properties of Guassian beams is to reduce the maximum on-axis intensity and increase the relative focal shift.In order to obtain the max imum intensity and less relative focal shift,the Gussian beam should be focused with bigger beam waist through thinner lenses with smaller focal length.