We present a novel moiré diagnostic that allows the time-averaged spatial coherence properties of soft-x-ray lasers to be measured. The technique is an extension of the theoretical work in a recent paper [J. Opt. Soc. Am. A <b>16</b>, 323 (1999)] and is based on the concept of decompositions of the far-field divergence for partially coherent beams. An appealing feature of the approach is that the spatial coherence width at other planes can be evaluated from the measured one at a given plane on the assumption of shape-invariant beams.
© 2000 Optical Society of America
(030.1640) Coherence and statistical optics : Coherence
(120.4120) Instrumentation, measurement, and metrology : Moire' techniques
(140.0140) Lasers and laser optics : Lasers and laser optics
(140.7240) Lasers and laser optics : UV, EUV, and X-ray lasers
(340.0340) X-ray optics : X-ray optics
Jun Yang, Dianyuan Fan, Shiji Wang, and Yuan Gu, "Moiré technique for spatial coherence measurements of soft-x-ray lasers," J. Opt. Soc. Am. A 17, 790-793 (2000)