The mathematical expressions for the coherent-mode decomposition of Bessel–Gauss (BG) beams have been derived for the general case, for which the cross correlation of modes is included, and the inverse problem of calculating the mode parameters from the given M<sup>2</sup> factor has been solved for BG beams.
© 1999 Optical Society of America
Bin Zhang and Baida Lü, "Coherent-mode decomposition of Bessel–Gauss beams," J. Opt. Soc. Am. A 16, 1413-1416 (1999)