涡旋光束轨道角动量干涉及检测的研究

Interference and Detection of Vortex Beams with Orbital Angular Momentum

分析了涡旋光与平面波的干涉现象,利用涡旋光共轴叠加干涉生成携带双态轨道角动量的光,并将其应用于轨道角动量拓扑荷数的检测。利用叉形错位光栅制备呈中心对称的涡旋光束,并讨论了在不同拓扑荷数情况下,利用两束涡旋光束干涉制备双态轨道角动量光束。数值模拟和实验结果表明,随着拓扑荷数的数值及正负的变化,两束涡旋光束干涉叠加后其干涉图像发生规律性的变化,据此可检测涡旋光束。涡旋光束在信息传输及编码方面具有重要意义,此研究为其在自由空间通信中的复用提供了实验依据,也为光通信系统的性能改善提供了可能。

The interference phenomenon of vortex beams and plane waves is analyzed. By using coaxial superpositioninterference of vortex beams, we can generate the light with binary orbital angular momentum, and apply it to thetopological charge number detection of orbital angular momentum. We use fork dislocation grating to generatecentrosymmetric vortex beams and then discuss the generation of light beams with binary orbital angular momentumby the interference of two vortex beams with different topological charge numbers. Numerical and experimentalresults show that with the ehange of the topological charge number value, either plus or minus, the interferenceimage which is generated by the interference superposition of two vortex beams is also changing regularly.According to this, vortex beams can be detected. Moreover, vortex beam has important significance in informationtransmission and coding. Our study provides experiment basis for the reuse of vortex beams in free spacecommunication, and provides potential for performance improvement of optical communication system.