基于二维叉形光栅的涡旋光束分束阵列产生

Vortex beam splitting array generation based on two-dimensional forked grating

首先设计了一种二维叉形光栅结构,并基于夫琅禾费衍射理论,得到了高斯光束通过该光栅的焦平面场分布表达式。数值模拟结果表明,当高斯光束通过二维叉形光栅调制后,在焦平面处产生了由不同拓扑荷涡旋光束组成的3×3涡旋光束阵列,且各个子光斑的拓扑荷数与光栅结构、衍射级次有关。其次,进行了实验验证。将二维叉形光栅相位图加载到空间光调制器SLM上,当高斯光束经SLM反射后,在焦平面处同样接收到3×3涡旋光束阵列,且与数值模拟的结果相符。研究结果表明,利用二维叉形光栅结构可实现涡旋光束分数阵列的产生,这将为不同拓扑荷涡旋光束的模式复用,实现光通信容量的增加技术支持,在光通信领域具有应用潜力。

In this paper,a two-dimensional forked grating structure is designed and the expression of the focal plane field distribution of Gaussian beam passing through the grating is obtained based on the Fronhofer diffraction the-ory.The numerical simulation results show that when the Gaussian beam is modulated by the two-dimensional forked grating,a 3×3 vortex beam array consisting of different topological charge vortex beams is generated at the focal plane,and the topological charge number of each subspot is related to the grating structure and the diffraction level.Next,ex-perimental verification was performed.The two-dimensional forked grating phase diagram was loaded into the spatial light modulator SLM,and when the Gaussian beam was reflected by the SLM,the 3×3 vortex beam array was also re-ceived at the focal plane,and the results were consistent with the numerical simulation.The results show that the gener-ation of fractional arrays of vortex beams can be achieved by using a two-dimensional forked grating structure,which will provide technical support for mode multiplexing of vortex beams with different topological loads to achieve increased optical communication capacity and has potential applications in the field of optical communication.