A method of studying the M~(2)-factor of truncated partially coherent beams both in free space and in turbulence is proposed, i.e., the method of the window function being expanded into a finite sum of complex-valued Gaussian functions. Taking the Gaussian Schell-model (GSM) beam as a typical example of partially coherent beams, the analytical formula of the M~(2)-factor of truncated GSM beams propagating through atmospheric turbulence is derived. It is shown that the M~(2)-factor decreases as the truncation parameter delta and the coherence parameter a increase. However, the M~(2)-factor in turbulence is more sensitive to delta than that in free space. On the other hand, the M~(2)-factor of truncated partially coherent beams with smaller delta is more affected by turbulence. In addition, the effect of turbulence on the M~(2)-factor of truncated GSM beams is less sensitive to the coherence parameter a than that of nontruncated GSM beams.
展开▼
