海洋湍流下涡旋光束经粗糙面的回波特性  

Echo Characteristics of Vortex Beam Passing Through Rough Surface Under Oceanic Turbulence

作　　者：吴鹏飞[1] 张咪 王姣 谭振坤 Wu PengFei;Zhang Mi;Wang Jiao;Tan ZhenKun(School of Automation and Information Engineering,Xi'an University of Technology,Xi'an 710048,Shaanxi,China;School of Electronic Information and Artificial Intelligence,Shaanxi University of Science and Technology,Xi'an 710021,Shaanxi,China;School of OptoElectronical Engineering,Xi'an Technological University,Xi'an 710021,Shaanxi,China)

机构地区：[1]西安理工大学自动化与信息工程学院,陕西西安710048 [2]陕西科技大学电子信息与人工智能学院,陕西西安710021 [3]西安工业大学光电工程学院,陕西西安710021

出　　处：《光学学报》2023年第12期64-72,共9页Acta Optica Sinica

基　　金：陕西省科技成果转移与推广计划项目(2020CGXNG-041);陕西省教育厅服务地方专项计划项目(20JC027);国家自然科学基金(62001363,62101313);陕西省重点研发计划工业领域一般项目(2022GY-100);陕西省科协青年人才支持项目(20220142)。

摘　　要：光场回波散射特性是未来水下激光通信与探测一体化的关键技术之一,而具有螺旋波前结构的涡旋光束[如拉盖尔-高斯(LG)光束]更适合抑制海洋湍流的影响。利用广义Huygens-Fresnel原理,推导出弱海洋湍流中LG光束经高斯分布粗糙表面反射的回波散斑强度的解析表达式;数值分析了光源参数、海洋湍流以及粗糙目标表面参数对回波散斑场复相干度的影响。结果表明,复相干度随着LG光束拓扑荷数、束腰半径、波长的增大而减小,随着海洋湍流强度的增大而降低,随着粗糙面相干长度的增加而增大,并且当粗糙表面的相干长度大于球形波在海洋湍流中传播的相干长度时,复相干度变化不明显,表明此时粗糙表面对复相干度的影响远小于海洋湍流的影响。这一结论为海洋湍流条件下目标探测与识别提供了参考。Objective The surface of the object which in nature is rough relative to the wavelength of light beams is a rough target.When the light is incident on the rough target,the beam will be scattered,and the receiving end will receive the light intensity pattern of alternating light and dark waves,which is called speckle pattern.The echo scattering characteristic of the light field is one of the key technologies for the integration of underwater laser communication and detection in the future.In ocean detection technology,underwater scattering technology,and underwater wireless optical communication technology,the transmission characteristics of beams through oceanic turbulence and echo characteristics of beams through the rough surface play a crucial role in turbulent conditions.The physical characteristics of the rough target surface(surface roughness,coherence length,deformation degree,motion velocity,and rotation velocity)play an important role in influencing echo characteristics.The current studies mainly adopt the fractal method,wavelet transform,deep learning,and other methods to process the laser speckle pattern collected at the receiving end.The surface roughness,deformation degree,translation velocity,and rotation velocity of the rough target can be identified.The current underwater detection technology is mainly laser,but the laser loss during detection is serious,thus resulting in limited rough target information reflected by the received speckle.Since the vortex beam features hollow intensity distribution,phase helix,and orthogonality of orbital angular momentum(OAM),it can carry more information than the Gaussian beam.LaguerreGaussian(LG)beams are typical vortex beams with significant advantages in light scattering and target recognition.At present,there are two aspects to study the scattering characteristics of light beams through rough targets.The first is the speckle characteristics of light beams through the rough surface in free space,and the second is the speckle characteristics of light beams thro

关 键 词：海洋光学 海洋湍流 拉盖尔-高斯光束 散斑 回波特性 复相干度 

分 类 号：O436[机械工程—光学工程]