部分相干径向偏振涡旋光焦场轨道角动量特性

将部分相干径向偏振涡旋光束的轨道角动量应用于焦场目标探测，根据部分相干及Richards-Wolf矢量衍射积分理论，推导了光束焦场目标平面处的光场分布，讨论了焦平面处的轨道角动量密度分布特性，分析了入射光束的相干长度和聚焦透镜的数值孔径对纵向分量轨道角动量密度分布和轨道角动量的影响。结果表明，随着相干长度的增大，轨道角动量和轨道角动量密度迅速变大，当增大至0.5 cm后，轨道角动量和轨道角动量密度的变化趋于平缓，此后，相干长度的变化不再影响轨道角动量和轨道角动量密度分布。随着数值孔径的增大，轨道角动量和轨道角动量密度始终表现出增长的变化趋势，并且，变化程度在数值孔径大于0.7后越来越大。

Orbital angular momentum properties of focal field for partially coherent radially polarized vortex beam

The orbital angular momentum of the partially coherent radially polarized vortex beam is applied to the focal field target detection.Based on the partially coherent and the Richards Wolf vector integral theory,the optical field distributions in the focal field target plane of the beam are derived.The distribution characteristics of the orbital angular momentum density in the focal plane are discussed.The influence of the coherence length of incident beam and the numerical aperture of focusing lens on the orbital angular momentum density distribution and the orbital angular momentum of the longitudinal component is analyzed.The results show that with the increase of the coherence length,the orbital angular momentum and the orbital angular momentum density rapidly increase.When it increases to 0.5cm,the changes of the orbital angular momentum and the orbital angular momentum density tend to be flat.Thereafter,the change of the coherence length no longer affects the orbital angular momentum and the orbital angular momentum density distribution.As the numerical aperture increases,the orbital angular momentum and the orbital angular momentum density always show a growing trend,and the change extent becomes larger after the numerical aperture is greater than 0.7.