分数阶双涡旋光束的实验研究

具有分数阶拓扑荷数的涡旋光束的产生及其传输是近几年来人们感兴趣的研究课题． 本文提出了一种新型的分数阶双涡旋光束, 该光束是由两束带有不同分数阶拓扑荷数的涡旋光束共轴叠加产生, 其光强分布为双环结构．我们对该光束分别进行了理论模拟和实验研究．研究表明, 分数阶双涡旋光束的双环携带不同的轨道角动量, 且相互独立地传输．这种新型的涡旋光束相对于整数阶或单个分数阶拓扑荷数的涡旋光束更具有控制多样性, 有望在光学镊子、光学扳手等微粒子操控领域开发新的应用．

Experimental study on fractional double-vortex beams

The generation of fractional vortex beams and their propagation have been interesting research topics in recent years. In this paper we introduce a new type of fractional double-vortex beam, which is generated by the coaxial superposition of the vortex beams with two different fractional topological charges, and its total intensity distribution is of double-ring. We study the generation of this kind of beam theoretically and experimentally. It is shown that the rings of the fractional double-vortex beams carry different orbital angular momenta, from each other and propagate independently. The fractional double-vortex beams possess diverse manipulations as compared with the vortex beams with integer or single fractional charges. Therefore, the fractional double-vortex beam will be of great significance in optical rotation and manipulation of microscopic particles.