畸变光束的焦斑质心位置

Centroid position of focal spot of laser beam with aberration

为分析振幅和相位发生畸变情况下光束焦斑质心位置所受的影响,以光波标量衍射理论中的夫琅和费衍射公式为基础,根据光斑强度分布一阶矩质心位置的定义,推导了直接依赖于光束近场复振幅分布的焦斑质心位置的一般表达式。进一步推导了焦斑质心位置对光束近场强度分布和相位斜率分布的依赖关系式,并对该式清晰的物理意义进行了阐述。利用焦斑质心位置表达式,可分析和确定由于振幅调制和相位畸变导致的质心位置偏移。最后,对无相位畸变和存在低阶泽尼克相位畸变情况下的简单畸变光束进行了相应的分析讨论。

In order to analyze the effect of aberration of amplitude and phase of laser beam on centroid position of focal spot, based on the Fraunhofer formula for light wave scaler diffraction theory, according to the definition of first order moment centroid position, the general expression of focal spot centroid position directly depending on the complex amplitude of near field is derived. The eentroid position of the focal spot diretly depending on intensity distribution and phase slope distribution of near field is derived, and its physical meaning is described. The excursion of centroid position of focal spot may be easily acquired with the centroid position expression of focal spot. At last the laser beam with simple aberration, such as no phase aberration and low order Zernike phase aberration, is analyzed.