The generalized M2-factor and coherent-mode decomposition of truncated flat-topped beams
截断平顶光束的广义M2因子和相干模分解

By using the definition of generalized second-order moments and complex Gaussian functions expansion of rectangular function, the analytical expressions for the generalized M2-factor and mode coherence coefficients of the new model of flat-topped beams introduced by Li have been derived. The mode correlation, mode structure, and coherent-mode decomposition of flat-topped beams have been analyzed. Theory of the coherent-mode decomposition of truncated flat-topped beams is built.