相干涡旋和刃型位错在海洋湍流中的相互作用  

Interaction Between Coherence Vortex and Edge Dislocation in OceanicTurbulence

作　　者：陈海涛[1] 高曾辉[2] Chen Haitao;Gao Zenghui(College of Physics and Engineering,Chengdu Normal University,Chengdu 611130,Sichuan,China;Computational Physics Key Laboratory of Sichuan Province,Yibin University,Yibin 644000,Sichuan,China)

机构地区：[1]成都师范学院物理与工程技术学院,四川成都611130 [2]宜宾学院四川省计算物理高校重点实验室,四川宜宾644000

出　　处：《中国激光》2024年第8期126-136,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金(61275203,61775188);四川省教育厅自然科学基金(18ZA0081)。

摘　　要：类比相干光束中刃型位错概念,提出一种新的相干奇点——相干刃型位错。对高斯-谢尔模光束携带的相干涡旋和刃型位错在海洋湍流中的相互作用进行研究。基于扩展的惠更斯-菲涅耳原理,得到了该光束在海洋湍流环境下的交叉谱密度表达式,并将其用于研究相干涡旋和刃型位错的相互作用。研究发现:相干刃型位错在相干涡旋的作用下发生断裂并转化成相干涡旋。在光束传输过程中,光场中有单个或成对相干涡旋的产生或湮灭现象发生。二者之间的作用特点不仅与传输距离有关,还受光束初始参数和海洋湍流参数的影响。二者之间的作用规律与自由空间光涡旋和刃型位错的作用规律不同。Objective It is well known that there are two typical phase singularities in the fully coherent beams,i.e.,the optical vortex and the edge dislocation.Although much of research has explored properties of the fully coherent beams,there are practical uses of the partially coherent beams because they are more resistant to degradation with propagation through turbulent medium than the former.The propagation of the partially coherent beams carrying coherence singularities in oceanic turbulence has attracted much attention due to its application in underwater wireless communication.It is interesting to ask how oceanic turbulence can affect the interaction of coherence vortex and edge dislocation carried by partially coherent beams.Because the Gaussian Schell-model beam is a typical example of partially coherent beams,the interaction of the coherence vortex and edge dislocation carried by the Gaussian Schell-model beams in oceanic turbulence is studied in detail.Mathods By making an analogy with definition of the edge dislocation in coherent beams,the coherence edge dislocation is shown to be in existence in partially coherent beams.Based on the extended Huygens-Fresnel principle,the analytical expression of the cross-spectral density for the Gaussian Schell-model beams carrying the coherence vortex and edge dislocation propagating through oceanic turbulence is derived,which is used to study the interaction of them in oceanic turbulence.The position of correlation singularities of the partially coherent beams at the z plane can be determined by the curves of the real component and imaginary component,as well as phase distribution of the spectral degree of coherence of the Gaussian Schell-model beams.Results and Discussions There should exist another type of coherence singularities,namely the coherence edge dislocation withπ-phase jump located along a line in the transverse plane of the correlation function,which is different from the edge dislocation in fully coherent beams(Fig.1),because the transverse edge dislocatio

关 键 词：激光光学 奇点光学 部分相干光束 相干奇点 相干涡旋 海洋湍流 

分 类 号：O436[机械工程—光学工程]