部分相干无衍射光束经环形孔径的传输特性

Propagation Properties of Partially Coherent Diffraction-free Beam Through an Annular Aperture

理论上利用高斯谢尔模型和交叉谱密度的传播公式得到部分相干Bessel光束经过环形孔径的光强表达式.通过Mathcad软件数值模拟光强表达式,得到在不同传播距离的截面光斑图,结果表明部分相干Bessel光束在经过环形孔径后会产生空心光束.实验中以绿光LED为光源,经轴棱锥聚焦得到部分相干Bessel光束,在其无衍射距离内放置环形孔径.使用体视显微镜照相系统拍摄部分相干Bessel光束经过环形孔径的衍射光斑图,得到的结果与模拟结果吻合.

Based on Gaussian-Schell model and method of the cross spectral density,the optical intensity formula of partially coherent Bessel beam passing through an annular aperture was derived theoretically.Mathcad software numerically was used to simulate the optical intensity formula,and the cross-sectional light spot diagrams of different propagation distance were derived.The results show that partially coherent Bessel beam passing through an annular aperture can generate a hollow beam.In experiment,green LED was used as the light source to obtain partially coherent Bessel beam focused by axicon,and an annular aperture was placed in its non-diffraction distance.The diffraction light spot diagram of partially coherent Bessel beam passing through the annular aperture was shot by a stereo microscope camera system,and the results agree with the simulation results.