Spatial correlation properties and phase singularity annihilation of Gaussian Schell-model beams in the focal region
Liu Pu-Sheng(刘普生)a) b) †, Pan Liu-Zhan(潘留占)c), and Lü Bai-Da(吕百达)b)
aSchool of Physical Electronics, University of Electronics Science and Technology of China, Chengdu 610054, China;b Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064, China; c Department of Physics, Luoyang Normal College, Luoyang 471022, China
Abstract By using the generalized Debye diffraction integral, this paper studies the spatial correlation properties and phase singularity annihilation of apertured Gaussian Schell-model (GSM) beams in the focal region. It is shown that the width of the spectral degree of coherence can be larger, less than or equal to the corresponding width of spectral density, which depends not only on the scalar coherence length of the beams, but also on the truncation parameter. With a gradual increase of the truncation parameter, a pair of phase singularities of the spectral degree of coherence in the focal plane approaches each other, resulting in subwavelength structures. Finally, the annihilation of pairs of phase singularities takes place at a certain value of the truncation parameter. With increasing scalar coherence length, the annihilation occurs at the larger truncation parameter. However, the creation process of phase singularities outside the focal plane is not found for GSM beams.
Received: 15 August 2007
Revised: 13 September 2007
Accepted manuscript online:
PACS:
42.25.Kb
(Coherence)
Fund: Project supported by
the National Natural Science Foundation of China (Grant No
10574097), and the Youth Foundation of University of Electronics
Science and Technology of China.
Cite this article:
Liu Pu-Sheng(刘普生), Pan Liu-Zhan(潘留占), and Lü Bai-Da(吕百达) Spatial correlation properties and phase singularity annihilation of Gaussian Schell-model beams in the focal region 2008 Chin. Phys. B 17 1752
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