Fabrication of Fresnel zone plates with 25 nm zone width using extreme ultraviolet holography

In this article we report the fabrication of Fresnel zone plates (FZP) by recording the interference pattern of converging and diverging spherical waves at extreme ultraviolet wavelength (λ=13.5nm). The spherical waves are generated by two concentric annular parent zone plates. The recorded pattern shows a factor of two reduction in the smallest feature size (outermost zone width) compared to its parent counterparts that generate the spherical waves. FZPs with a zone width down to 16 nm have been recorded with this technique. We also present scanning transmission X-ray microscopy (STXM) results taken with a zone plate with 25 nm outermost zone width.