Coherence vortices of partially coherent beams in the far field

• 来源期刊: 中国物理（英文版）
• 关键词: singular optics coherence vortex in the far field partially coherent beam Schell-model correlator Gaussian envelope
• 年，卷（期）: 2007,（2）
• 页码范围: 411-415
• 页数: 5页
• 语种: 英文

摘要

Based on the propagation law of cross-spectral density function, studied in this paper are the coherence vortices of partially coherent, quasi-monochromatic singular beams with Gaussian envelope and Schell-model correlator in the far field, where our main attention is paid to the evolution of far-field coherence vortices into intensity vortices of fully coherent beams. The results show that, although there are usually no zeros of intensity in partially coherent beams with Gaussian envelope and Schell-model correlator, zeros of spectral degree of coherence exist. The coherence vortices of spectral degree of coherence depend on the relative coherence length, mode index and positions of pairs of points.If a point and mode index are kept fixed, the position of coherence vortices changes with the increase of the relative coherence length. For the low coherent case there is a circular phase dislocation. In the coherent limit coherence vortices become intensity vortices of fully coherent Laguerre-Gaussian beams.