像散离焦检测系统中光斑能量中心偏移对测量精度的影响

Effect of the center deviation of focusing spot on the measurement precision in the astigmatic defocus detecting system

通过推导高斯光条件下像散离焦检测系统中离焦量与聚焦误差信号功率之间的关系,分析了激光光斑能量中心相对四象限探测器几何中心的偏移距离和偏移角对离焦量测量精度的影响及其规律。在此基础上,提出了一种易于实现、能够精确定位四象限探测器的实验方法,该方法能够有效地提升系统抗干扰能力和探测精度,减小系统误差,加强系统稳定性。此过程对设计搭建高精度像散离焦检测系统具有重要的指导意义。

By deriving the relation between the defocus and the power of focusing error signal in the astigmatic defo cus detecting system under the case of Gaussian light spot, the influences and regulars of the deviated distance and angle between the laser energy center and the four-quadrant detector center on the precision of defocus detection are analyzed. On the above basis, an easy performed high accuracy positioning method is proposed, which can strengthen the capacity of resisting disturbance and the accuracy of measurement. The process on establishing a high accuracy astigmatic method based on defocus detecting system has an important guiding significance.