摘要
推导出了部分相干平顶光束在湍流大气中传输的等效曲率半径的解析表达式,详细地研究了湍流对其等效曲率半径的影响.研究表明,湍流使得等效曲率半径R减小,但是只有当湍流足够强时等效曲率半径极小值出现的位置zmin才会改变.在弱湍流中,R随着光束相干长度β的增大而增大;但是在强湍流中,R随着β的增大而减小.R随着光束阶数M(N)的增大而缓慢减小.若β越大、M(N)越小,则R受湍流的影响越大.此外,部分相干平顶光束在自由空间中传输时远场均可以看作球面波,这一结果与光束参数无关.但是,在湍流大气中不论是近场还是远场等效曲率半径均与光束参数有关.
The analytical expression for the effective radius of curvature R of a partially coherent flat-topped beam propagating through atmospheric turbulence is derived. It is shown that R decreases due to turbulence. However,position zminwhere R reaches its minimum will change due to the turbulence when the strength of turbulence is strong enough. The effective radius of curvature R increases with the increase of beam coherence parameter β when the strength of turbulence is weak, while R decreases with β increasing when the strength of turbulence is strong. The R decreases slowly with the increase of beam order M（N）. The R of partially coherent flat-topped beam with larger β and smaller M（N） is more sensitive to turbulence. In addition,in free space the wavefront of partially coherent flat-topped beam can be regarded as a spherical surface in the far-field,which is independent of the beam parameters. However,in turbulence the effective radius of curvature depends on the beam parameters in the near field and also in the far field.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第6期3953-3958,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:60778048)资助的课题~~
关键词
等效曲率半径
湍流
部分相干平顶光束
effective radius of curvature
turbulence
partially coherent flat-topped beam
