›› 2014, Vol. 23 ›› Issue (9): 94202-094202.doi: 10.1088/1674-1056/23/9/094202

• ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS • 上一篇    下一篇

Scattering of a general partially coherent beam from a diffuse target in atmospheric turbulence

王利国a, 吴振森a, 王明军b, 曹运华a, 张耿a   

  1. a Science School, Xidian University, Xi'an 710071, China;
    b Institute of E. M. Wave Propagation & Scattering, Xianyang Normal College, Xianyang 712000, China
  • 收稿日期:2013-11-06 修回日期:2014-02-07 出版日期:2014-09-15 发布日期:2014-09-15
  • 基金资助:
    Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. K5051207001) and the National Natural Science Foundation of China (Grant Nos. 61172031 and 61271110).

Scattering of a general partially coherent beam from a diffuse target in atmospheric turbulence

Wang Li-Guo (王利国)a, Wu Zhen-Sen (吴振森)a, Wang Ming-Jun (王明军)b, Cao Yun-Hua (曹运华)a, Zhang Geng (张耿)a   

  1. a Science School, Xidian University, Xi'an 710071, China;
    b Institute of E. M. Wave Propagation & Scattering, Xianyang Normal College, Xianyang 712000, China
  • Received:2013-11-06 Revised:2014-02-07 Online:2014-09-15 Published:2014-09-15
  • Contact: Wang Ming-Jun E-mail:wuzhs@mail.xidian.edu.cn
  • Supported by:
    Project supported by the Fundamental Research Funds for the Central Universities of China (Grant No. K5051207001) and the National Natural Science Foundation of China (Grant Nos. 61172031 and 61271110).

摘要: The second-order and fourth-order statistical moments of the speckle field from a diffuse target in atmospheric turbulence are studied which have great influence on the performance of lidar systems. By expanding a general rotationally symmetric beam as a sum of Gaussian-Schell model (GSM) beams, the mean intensity of the general beam propagating over a distance in an atmospheric turbulence is formulated. Expressions for the degree of coherence (DOC) and the normalized intensity variance of the scattered field of a general beam from a rough surface in turbulence are derived based on the extended Huygens-Fresnel principle. The general expressions reduce to the well-known forms for a GSM beam. Another example for the general beam used in this paper is the collimated flat-topped beam. The results of both kinds of beams show that the intensity profile on the target plane is a key factor affecting the statistical characteristics of the speckle field. A larger beam spot on the target plane induces a smaller coherence length and a smaller normalized intensity variance of the received field. As turbulence gets stronger, the coherence length becomes smaller, and the normalized intensity variance firstly increases and declines to unity finally.

关键词: atmospheric optics, extended Huygens-Fresnel principle, partially coherent beam, degree of coherence

Abstract: The second-order and fourth-order statistical moments of the speckle field from a diffuse target in atmospheric turbulence are studied which have great influence on the performance of lidar systems. By expanding a general rotationally symmetric beam as a sum of Gaussian-Schell model (GSM) beams, the mean intensity of the general beam propagating over a distance in an atmospheric turbulence is formulated. Expressions for the degree of coherence (DOC) and the normalized intensity variance of the scattered field of a general beam from a rough surface in turbulence are derived based on the extended Huygens-Fresnel principle. The general expressions reduce to the well-known forms for a GSM beam. Another example for the general beam used in this paper is the collimated flat-topped beam. The results of both kinds of beams show that the intensity profile on the target plane is a key factor affecting the statistical characteristics of the speckle field. A larger beam spot on the target plane induces a smaller coherence length and a smaller normalized intensity variance of the received field. As turbulence gets stronger, the coherence length becomes smaller, and the normalized intensity variance firstly increases and declines to unity finally.

Key words: atmospheric optics, extended Huygens-Fresnel principle, partially coherent beam, degree of coherence

中图分类号:  (Wave propagation, transmission and absorption)

  • 42.25.Bs
42.55.Ah (General laser theory) 42.68.Bz (Atmospheric turbulence effects) 42.30.Ms (Speckle and moiré patterns)