Young's interferograms with high visibility reveals a high degree of spatia
l coherence of first order. But, spatially partial coherence of second orde
r can be observed when it interferes itself through a compensated Michelson
's interferometer attached at the exit of the Young's slit pair. We show th
at the patterns at the exit of the Michelson's interferometer are Young's i
nterferograms with modulation fringes, which allow an estimation of the deg
ree of the high order spatial coherence. (C) 1998 Elsevier Science Ltd. All
rights reserved.