多环涡旋光束的实验研究

涡旋光束的产生、传输与应用是当前光学领域热门的研究课题之一.本文提出的新型多环涡旋光束,包括双环涡旋及三环涡旋光束,它是由多束携带不同拓扑电荷数且束腰半径不同的拉盖尔-高斯涡旋光束共轴叠加而成,其光强分布为多环结构.从理论上研究了多环涡旋光束的形成与分布特征,基于共轭对称延拓Fourier计算全息方法生成了多环涡旋光束的计算全息图,并利用一个空间光调制器实验产生了与理论一致的高质量的多环涡旋光束.研究表明多环涡旋光束的各环携带不同的轨道角动量,空间分布保持相互独立.这种新型的多环涡旋光束相对于携带单一拓扑电荷数的涡旋光束,提供了更多的控制参数和更加多样化的结构分布,因此在光学镊子、光学捕获等微操控以及光通信领域具有潜在的应用潜力.

Experimental study on multiple-ring vortex beams

The generation, propagation and application of vortex beams have been hot research topics in recent years. In this paper we introduce the novel multiple-ring vortex beams, including double-ring vortex beams and triple-ring vortex beams, which are generated by the coaxial superposition of multiple Laguerre-Gaussian vortex beams with different topological charge numbers and different waist parameters, and their intensity distribution is of multiple-ring. We study the generation and distribution characteristics of multiple-ring vortex beams theoretically, obtain the computer generated hologram of multiple-ring vortex beams based on conjugate symmetric extension Fourier computer generated holography, and experimentally generate quality multiple-ring vortex beams using a spatial light modulator. Excellent agreement between theoretical and experimental results is observed. The study indicates that each ring of multiple-ring vortex beams carries different orbital angular momentum, and the spatial distribution is independent. The novel multiple-ring vortex beams provide more controllable parameters and more diverse structure distributions, which enable their applications in the fields of micro-manipulation as optical tweezers or optical spanner. Furthermore, they also have potential applications as available encoding tools in optical communication.
Keywords： vortex beam topological charge computer-generated hologram spatial light modulator