Microscopy with a Fresnel Zone Plate (FZP)
Soft X-ray microscopy possesses several advantages compared to
electron microscopy. Firstly, the sharp X-ray absorption dependence
on elements and/or wavelength makes microscopy sensitive to elemental
composition possible. Secondly, natural specimens can be observed
directly without any fixing and staining. A FZP is a circular
transmission diffraction grating consisting of alternate opaque and
transparent rings. It gives a spatial resolution almost equal to its
outermost zone width. The FZPs in use were supplied by the Lawrence
Berkeley Laboratory. Since their outermost zone width is 50 nm,
a corresponding resolution can be expected. A resolution
of about 50 nm has been achieved as shown in the picture.
Magnified image outermost zones of a FZP
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