摘要涡旋光束是近年来的一个热门研究课题，其具有特殊的螺旋形波前结构，在微粒操纵、量子通信和生物医学方面有广泛的应用前景。本文首先通过Matlab对传输过程中的拉盖尔-高斯涡旋光束展宽进行了二维模拟,得出光斑展宽随着传输距离的变大逐渐变大。然后根据菲涅尔衍射积分公式，推导出离轴椭圆涡旋光束在拓扑荷为±1的情况下在自由空间中传输的解析表达式，并通过数值模拟详细地研究了离轴椭圆涡旋光束的光强分布和相位奇点在自由空间的传输特性。结果表明，传输过程中光强分布会发生明显的变化，对于相位奇点的传输，非离轴情况下，奇点一直位于光轴上；离轴情况下，相位奇点的位置随传输距离的增加而改变，沿椭圆短轴方向离轴和沿长轴方向离轴的情况会略有不同。79009

毕业论文关键词  拉盖尔-高斯涡旋光束  传输  离轴涡旋光束   离轴参量

毕业设计外文摘要

Title    The properties of vortex beam transmission           

Abstract Vortex beam is a popular research topic in recent years, it has special structure of the spiral wave front。 And vortex beam has broad applicatiion prospects in the particle manipulation, quantum communication and biological medicine。 The spot broadening and phase distribution of vortex beams which generation in a spiral phase of change during transmission were analyzed theoretically。 Based on the Fresnel diffraction integral, the analytical expression for the propagation of off-axis elliptical vortex beams with topological charge ±1 in free space is derived, which is used to study the intensity distribution and propagation of phase singularity of off-axis elliptical vortex beams in detail by numerical simulation。 The results show that the intensity distributions of beams will change significantly while propagation。 For the propagation of phase singularity, the position of phase singularity is always on the optical axis in the case of on-axis, and changes in the case of off-axis。 The situation of off-axis direction along the minor axis and the situation of off-axis along the major axis are different while propagation。

Keywords  Laguerre-gaussian  vortex beam  Transmission  Off-axis vortex beam The off-axis parameter

目   次

1  引言 1

1。1  背景及意义 1

1。2  发展现状 1

1。3  当前涡旋光束的应用价值 2

1。4  研究的主要内容 5

2  涡旋光束的产生 6

2。1计算全息法 6

2。2空间光调制器(Spatial Light Modulator) 6

2。3 螺旋相位板法 8

3  Gauss光束在理想状态下的传输特性 10

3。1 理论概述 10

3。2 数值仿真与分析 11

4  Laguerre-Gaussian光束的传输特性 13

4。1  涡旋光束的传输理论 13

4。2  传输过程光斑的展宽