硬边衍射超高斯光束传输特性的自收敛束宽法研究

用自收敛束宽法,对有硬边衍射超高斯光束束宽的传输及其参数作了研究,研究表明,当自收敛束宽因子满足一定条件时,超高斯光束的自收敛束宽与基于无截断二阶矩定义的束宽遵循相同的传输规律,因此,自收敛束宽法定义的光束传输因子在传输过程中保持不变。还对自收敛束宽法和渐近近似法作了详细比较,对这两种方法的等价性作了讨论,并且对自收敛束宽法赋予了简明的物理含义。

Propagation Properties of Hard-edge Diffracted Super-Gaussian Beams by Using the Self-convergent Beam Width Method

Using the self-convergent beam width method, the beam width propagation and beam-propagation parameters of hard-edge diffracted super-Gaussian beams are studied. It is found that the self-convergent beam width of super-Gaussian beams obeys the same law as that of the beam width based on the second-order moments without truncation, when the self-convergent-width factor satisfies a certain condition. Therefore, the beam propagation factor (M2-factor) obtained by using this method is invariable upon propagation. Meanwhile, a detailed comparison between the self-convergent beam width method and the asymptotic approach is made and the equivalence between the two methods is discussed. In addition, a concise physical meaning of the self-convergent beam width method is given.