Comments on “M2 factor and mode coefficients of partially coherent Gaussian beams”

The Errors in the paper entitled “M2 factor and mode coefficients of partially coherent Gaussian beams” (X. Chu and B. Zhang) published in 〈High Power Laser & Particle Beams〉12(6), (Nov.), 2000 (cited as Chu's paper) are point out and analyzed physically. First, the new result could not be found in Chu's paper, because the same method and same results were given in Ref. ［1］ and ［2］ published in 〈Opt. Lett.〉, 23 (13) July, 1. 1998 (Gori F, Santarsiero M, Borghi R, and Guattari G), and , 38(25), Sept. 1, 1999 (Santarsiero M, Gori F, Borghi R, and Guattari G.) , respectively. Moreover, in Chu's paper any physical interpretation about the subjects "how to determine the waist size v0 in a unique way" and "how to experimentally realize their partially coherent Gaussian beam