贝塞尔光束的简易实现方法

对光纤中传播的电磁场分析发现,其纵向分量可以用贝塞耳函数及第二类变态贝塞耳函数来描述,据此,提出一种利用玻璃毛细管和聚焦透镜实现贝塞尔光束的简易方法.通过观察发现,在光束传播方向,出射光束即为贝塞尔光束,沿光束传播方向的光强分布不会发生改变,仅产生扩散.研究表明,随着聚焦透镜的焦距f的变大,贝塞尔光束的高瓣数光环的光强变弱,光束的光强向低瓣数光环和中心光斑移动;随着毛细管长度l的增加,光束的高瓣数的光环光强在不断增强.此外,研究还表明,透镜与毛细管端面之间距离d对于出射光束横截面上的光强分布有很大的影响.

A Simple Approach for Generating Bessel Beams

The longitudinal component of electromagnetic wave propagating in fiber can be expressed by Bassel function or the modified Bessel function of second kind.Based on this principle,we put forward a simple method for generating a Bessel beam with glass capillary and focusing lens.It is found that the beam in the output plane is Bessel beam.The intensity profile of such a beam keeps invariant with the increasing of propagation distance and only diffusing observed.It is also found with the increasing of focus length,the intensity of outer annulus becomes weaker,and the inner annulus and the peak become stronger.Moreover the intensity of outer annulus of beam increases with the increasing of the length of capillary.In addition,the distance between the lens and the input plane of capillary plays an important role in the intensity profile Bessel beams.