Abstract
Coherence properties of an x-ray point focusing method, using flat crystals with modulated structures, are presented. The diffraction limit of the optics is derived for a given monochromatic point source. Within the energy range 8–16 keV, Si (111) and quartz (110) reflections are used to demonstrate the minimum achievable focus sizes to be 0.058 and 0.18 µm, corresponding to the source sizes of 5 and 13 µm, respectively. Calculations of the distribution of the Bragg diffraction amplitude indicate that the focusing method is well suited for synchrotron radiation sources. The criteria for achieving minimum focus size, when an x-ray source with a finite source size and a wavelength spread is considered, are obtained based on the concept of the spatial coherence length.
© 1997 Optical Society of America
Full Article | PDF ArticleMore Like This
W. Z. Chang and E. Förster
J. Opt. Soc. Am. A 14(7) 1647-1653 (1997)
G. E. Ice and C. J. Sparks
J. Opt. Soc. Am. A 11(4) 1265-1271 (1994)
P. Cloetens, J. P. Guigay, C. De Martino, J. Baruchel, and M. Schlenker
Opt. Lett. 22(14) 1059-1061 (1997)