中国物理B ›› 1999, Vol. 8 ›› Issue (2): 81-88.doi: 10.1088/1004-423X/8/2/001

• •    下一篇

GENERALIZED SIEGMAN FORMULA AND COMMENTS ON THE INEQUALITY M2≥1 FOR LIGHT-BEAM QUALITY

盛正卯, 杨焕雄   

  1. Department of Physics, Hangzhou University, Hangzhou 310028, China
  • 收稿日期:1998-05-25 修回日期:1998-10-06 出版日期:1999-02-15 发布日期:1999-02-20
  • 基金资助:
    Project supported Partly by the State Education Commission of China and by the Natural Science Foundation of Zhejiang Province (Grant No.196026), China.

GENERALIZED SIEGMAN FORMULA AND COMMENTS ON THE INEQUALITY M2≥1 FOR LIGHT-BEAM QUALITY

Sheng Zheng-mao (盛正卯), Yang Huan-xiong (杨焕雄)   

  1. Department of Physics, Hangzhou University, Hangzhou 310028, China
  • Received:1998-05-25 Revised:1998-10-06 Online:1999-02-15 Published:1999-02-20
  • Supported by:
    Project supported Partly by the State Education Commission of China and by the Natural Science Foundation of Zhejiang Province (Grant No.196026), China.

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摘要： An generalized version of the Siegman formula which comes directly from Helmholtz equation is reported in this paper. Based on this formula, a comparison between the two definitions of the light beam far-field divergence angle is made. It is discovered the Siegman's moment definition for divergence angle would not make sense if the light beam could not be approximated to the slowly varying one. The proof of inequality M2≥1 given by Chen and Qiu would fail if the evanescence wave effects are considered.

Abstract: An generalized version of the Siegman formula which comes directly from Helmholtz equation is reported in this paper. Based on this formula, a comparison between the two definitions of the light beam far-field divergence angle is made. It is discovered the Siegman's moment definition for divergence angle would not make sense if the light beam could not be approximated to the slowly varying one. The proof of inequality M2≥1 given by Chen and Qiu would fail if the evanescence wave effects are considered.

中图分类号:  (Beam characteristics: profile, intensity, and power; spatial pattern formation)

  • 42.60.Jf
02.30.Jr (Partial differential equations)