R. Borghi et M. Santarsiero, MODAL DECOMPOSITION OF PARTIALLY COHERENT FLAT-TOPPED BEAMS PRODUCED BY MULTIMODE LASERS, Optics letters, 23(5), 1998, pp. 313-315
We present a simple mathematical model giving a possible description o
f a partially coherent light beam exhibiting a flat-topped transverse
intensity profile. Such a model allows us to deduce the modal distribu
tion inside a multimode stable optical cavity, assuming that the modes
are of the Hermite-Gauss type. The analytical expression used to repr
esent flat-topped profiles is of the flattened Gaussian type and leads
to an exact, closed-form expression for the M-2 factor of the output
beam. An analogous procedure could be used to treat the general proble
m of deducing the modal distribution inside a laser cavity starting fr
om intensity measurements of the output beam. (C) 1998 Optical Society
of America.