受光阑限制贝塞耳-高斯光束的衍射特性

Diffraction characteristics of Bessel-Gauss beams limited by apertures

对贝塞耳-高斯光束经不同几何构形光阑的衍射作了比较研究。结果表明,在选取合适的光阑参数情况下,锯齿光阑能减弱所关心区域(F=20)轴上光强的衍射调制,而超高斯光阑能抑制大部分菲涅耳区(F>3.7)的衍射调制。锯齿光阑和超高斯光阑都有较大的填充因子,使用合适的超高斯光阑可得到有较大填充因子(如fSuper-Gaussian=0.25)又更平滑的横向光强分布。数值计算说明,为有效抑制光强的衍射调制,适当选取超高斯光阑的阶数n和半宽ws(如n=4,ws=0.4mm)是必要的。

The diffraction of Bessel-Gauss beams by apertures with different geometries was studied and compared. If the aperture parameters are chosen appropriately, the serrated aperture will enable us to reduce the diffraction modulations of axial intensity in the region which we are interested in （F=20）, Furthermore, the super-Gaussian aperture can suppress the diffraction modulations in the most of Fresnel region （F 〉3.7）. Both the serrated and super-Gaussian apertures can maintain a relatively large filling factor, Thus, a smoother transversal intensity profile with relatively large filling factor （e,g, fSuper-Gaussian =0.25） can be achieved by using a suitable super-Gaussian aperture, Numerical calculations indicate that, in order to effectively suppress the diffraction modulations of intensity, it is necessary to choose the order n and half-width ws of super-Gaussian apertures （e.g. n=4, ws=0.4mm） properly.