Far-field divergence of a vectorial plane wave diffracted by a circular aperture from the vectorial structure

Based on the vectorial structure of an electromagnetic wave, the analytical and concise expressions for the TE and TM terms of a veetorial plane wave diffracted by a circular aperture are derived in the far-field. The expressions of the energy flux distributions of the TE term, the TM term and the diffracted plane wave are also presented. The ratios of the power of the TE and TM terms to that of the diffracted plane wave are examined in the far-field. In addition, the far-field divergence angles of the TE term, the TM term and the diffracted plane wave, which are related to the energy flux distribution, are investigated. The different energy flux distributions of the TE and TM terms result in the discrepancy of their divergence angles. The influences of the linearly polarized angle and the radius of the circular aperture on the far-field divergence angles of the TE term, the TM term and the diffracted plane wave are discussed in detail. This research may promote the recognition of the optical propagation through a circular aperture.

平面波微小圆孔矢量衍射理论的比较研究

文章以平面波的微小圆孔衍射为例,对矢量衍射场的级数解、非傍轴近似解以及精确积分解进行了详尽的数值计算,并对级数解、非傍轴近似解的有效性作了定性分析和比较研究。结果表明,平面波经微小圆孔衍射的级数解、非傍轴近似解的有效性与级数解阶次、光阑孔径及传播距离有关,2种解的有效适用范围具有一定的互补性;当光阑孔径与波长相当或小于波长时,衍射场的纵向分量不能忽略,必须考虑光场的矢量非傍轴特性。

高斯光束经圆形光阑衍射的远场发散特性

线偏振高斯光束经圆形光阑衍射后,其远场可表示成互相正交的横电(TE)项和横磁(TM)项之和。利用TE项和TM项的远场能流分布,导出了高斯衍射光束的TE项和TM项远场功率的解析表达式,由此可度量TE项和TM项在远场占总功率的比例。基于能流二阶矩的定义,给出了高斯衍射光束、TE项和TM项远场发散角的解析式以及三者远场发散角间的关系通式,重点分析了f参数和截取参数对远场发散角的影响。结果表明:随着f参数的增大,远场发散角先增大后趋向于各自的饱和值。截取参数对远场发散角的影响与f参数相关,当f参数较大时,截取参数对远场发散角的影响不明显;当f参数适中时,随着截取参数的增大,远场发散角先减小后趋向于各自的最小值;但当f参数较小时,高斯衍射光束和TM项二者的远场发散角出现一定的波动性。

用于毫米波焦面阵成像的小F数透镜焦区矢量衍射场分析

采用射线追迹法和Stratton Chu衍射积分公式研究透镜像空间的矢量衍射场 ,说明了决定衍射场分布样式的口径场相位分布的确定方法 ,对双曲面透镜给出了不同入射倾角时的焦区场功率分布 ,计算结果与实验吻合 .并考察了焦区场的矢量特性 ,计算与实验在毫米波频段完成 .

表面等离子体无掩膜干涉光刻系统的数值分析(英文)

表面等离子体激元具有近场增强效应,可以代替光子作为曝光源形成纳米级特征尺寸的图像.本文数值分析了棱镜辅助表面等离子体干涉系统的参量空间,并给出了计算原理和方法.结果表明,适当地选择高折射率棱镜、低银层厚度、入射波长和光刻胶折射率,可以获得高曝光度、高对比度的干涉图像.入射波长为431nm时,选择40nm厚的银层,曝光深度可达200nm,条纹周期为110nm.数值分析结果为实验的安排提供了理论支持.