方形涡旋光束在Nd:YAG介质中放大特性的数值研究  

Numerical study of amplification characteristics of square vortex beams in Nd:YAG media

作　　者：汤燕华 马再如 TANG Yanhua;MA Zairu(Department of Physics,School of Science,Xihua University,Chengdu 610039,China)

机构地区：[1]西华大学理学院物理系,成都610039

出　　处：《激光杂志》2025年第3期22-33,共12页Laser Journal

基　　金：四川省科技支撑计划项目(No.2014GZ0003)。

摘　　要：涡旋光束是当前研究热点之一,随着研究的深入,其在介质中的传输特性也得到了关注。基于非线性波动方程,采用分步傅里叶算法数值模拟方形涡旋光束在Nd:YAG介质中放大特性。研究了方形涡旋光束的拓扑荷数、入射峰值光强、束腰宽度和光束阶数等参数对其强度、频谱和B积分等方面的影响。数值研究结果表明:方形涡旋光束经过Nd:YAG介质放大后,其中心位置的强度起伏较强,而光束边缘强度起伏较弱;出射光束中心区域位置的强度呈连续振荡变化,对角方向上位置的强度要强于轴向中心方向。较小的拓扑荷数和较大的束腰宽度的方形涡旋光束可以减缓光束通过Nd:YAG介质后中心强度振荡,降低克尔效应对光束放大的影响。另外,减小Nd:YAG介质的厚度可以降低光束中心强度增强程度,并可以减小B积分的大小。Vortex beam is one of the current research hotspots,with the deepening of research,its transmission characteristics in the medium has also been paid attention to.Based on the nonlinear wave equation,the split-step Fourier algorithm is used to numerically simulate the amplification characteristics of square vortex beams in Nd:YAG media.The effects of topological charge,incident peak light intensity,beam waist width and beam order on the intensity,spectrum and B-integral of a square vortex beam are studied.The numerical results show that when the square vortex beam is amplified by Nd:YAG medium,the intensity fluctuation of the center position is stronger,but the intensity fluctuation of the edge of the beam is weaker.The intensity of the central region of the outgoing beam oscillates continuously,and the intensity in the diagonal direction is stronger than that in the axial direction.Small topological charge and large waist width of the square vortex beam can slow down the central intensity oscillation of the beam through Nd:YAG medium,and reduce the influence of Kerr effect on beam amplification.In addition,reducing the thickness of the Nd:YAG medium can reduce the intensity of the beam center and reduce the size of the B-integral.

关 键 词：非线性光学 波动方程 分步傅里叶算法 方形涡旋光束 B积分 

分 类 号：O437[机械工程—光学工程]