坐标缩放激光角谱传输及在激光光学系统中的应用

Angular-spectrum method with scaling factor and its applications to design of laser focus optical system

提出了坐标可缩放的激光传输角谱算法,用于评估激光光学系统性能并分析其系统公差。考虑Collins公式可用于计算激光光束在光学系统中的衍射传输过程,对该积分公式进行了坐标代换,将衍射积分公式转换为角谱传输过程,并引入坐标缩放因子,实现了目标面尺寸的自由选择,提高了激光传输计算的准确性。设计了一套激光传输系统,定义占有86.5%桶中功率的光斑尺寸为光斑半径,用提出的算法对激光光束传输公差进行了分析。分析表明：作用距离为90m时,焦面激光光斑的半径为0.8~1.4mm,期望值为0.92mm,实验测量值为1.01mm;作用距离为49m时,焦面激光光斑的半径为0.42~0.73mm,期望值为0.48mm,实验测量值为0.46mm,实验结果与公差分析相符。另外,通过公差分析验证了激光光束在光学系统中的焦移现象。由角谱法对激光传输系统的理论分析与实验结果相符,证明了该方法用于激光聚焦光学系统设计的可行性。

An angular-spectrum method with a scaling factor between the observation and the source plane was proposed for the laser propagation in an optical system to evaluate its performance and to analyze its tolerance.As the laser diffraction propagation in the optical system could be calculated by the Collins integral formula,the formula coordinate was transformed and an angular spectrum method was derived by coordinate substitution.Then,a scaling factor was introduced to make the choice of the observation-plane more flexibility and the calculation of the laser propagation more accurate.A laser optical system was designed,and its tolerance was analyzed by the angular-spectrum method.The evaluating criterion was the laser spot radius in the far field,which was defined by 86.5% Powerin Bucket（PIB）.Experiments show that when the radius of the laser spot is 0.8—1.4 mm in a distance of 90 m,the expected value calculated by the tolerance analysis is 0.92 mm and the measured result is 1.01 mm.Moreover,when that is 0.42—0.73 mm in the distance of 47 m,the expected value and the measured result are 0.48 mm and 0.46 mm,respectively.Both the experiment results match the data of the tolerance analysis well.The focal shift for laser propagation in the optical system was validated by the tolerance analysis.The theoretical analysis by the proposed method is verified experimentally,which confirms the feasibility proposed method in design of laser focus optical systems.