部分相干光在大气湍流中的光束扩展及角扩展  

Expansion and angular spread of partially coherent beam propagating in atmospheric turbulence

作　　者：柯熙政[1] 王婉婷[1] 

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

出　　处：《红外与激光工程》2015年第9期2726-2733,共8页Infrared and Laser Engineering

基　　金：国家自然科学基金(61377080;60977054;61271110);陕西省自然科学基础研究计划(2013JQ8011);陕西省教育厅科研计划(2013JK1104);陕西省工业攻关科技计划(2013K06-08)

摘　　要：基于广义惠更斯-菲涅耳原理、交叉谱密度函数,利用修正Von Karmon谱模型以及ITU-R颁布的大气折射率结构常数模型,推导出部分相干高斯-谢尔光束在大气湍流中传输时的束宽及角扩展表达式,讨论并对比斜程和水平两种传输方式下天顶角、传输距离、湍流强度、相干长度等参数对光束束宽与角扩展的影响,同时分别从相对束宽和相对角扩展的角度分析各种参数对于光束抑制湍流能力的影响,并给予相应的物理解释。结果表明:当天顶角小于π/3时,光束在斜程传输时的光束扩展和角扩展量接近于垂直传输,所受湍流影响很小。传输距离大于1 km时,束宽和相对束宽随传输距离的增加而明显增加。光束相干长度越大,光束所受湍流影响越大,而束宽及角扩展会随之减小。The generalized Huygens-Fresnel principle and the cross-spectral density function were used to derive the expressions of beam width and angular spread of partially coherent Gaussian-Schell beam when it was propagating in the atmosphere on the basis of the model of the modified Von Karmon spectrum and the atmospheric refractive-index structure constant issued by ITU-R. And then, the impact on the beam propagating in the slant and horizontal ways, caused by the zenith, the transmission distance, the turbulent intensity, the coherent length of the beam and other parameters, were discussed and compared. The impact of the parameters on the ability of anti-turbulence of the beam was analyzed from the perspective of the relative expansion and the relative angular spread respectively and a series of concrete explanations were given. The research results demonstrate that the expansion and the angular spread of the beam suffer little effect from the turbulence during slant path when the zenith is less than π/3, which is close to vertical transmission. The beam width and the relative beam width of the beam increase with the increasing transmission distance significantly when the distance is greater than 1 km. The larger the coherent length of the beam is, the greater the impact of the turbulence suffers, while the expansion and the angular spread decrease.

关 键 词：部分相干光 斜程传输 光束扩展 角扩展 

分 类 号：O43[机械工程—光学工程]