A soft-x-ray Mach-Zehnder interferometer configuration that makes use
of the time delay introduced by diffraction gratings to conduct single
-shot measurements of the linewidth of soft-x-ray laser amplifiers is
proposed and analyzed. The scheme was experimentally demonstrated in t
he near-IR region of the spectrum by measurement of the mode separatio
n of a semiconductor laser. A symmetric configuration with compensated
time delays that can be implemented for plasma diagnostics and for ev
aluating soft-x-ray optics is also discussed. (C) 1996 Optical Society
of America.