Nanostructuring of free-standing zone plates

Abstract

A method for the fabrication of free-standing silicon zone plates is presented. Free-standing zone plates with 100 nm and 50 nm outermost zone width and a diameter of 270 μm and 540 μm, respectively, have been fabricated. The zone plates are designed for focusing a neutral, ground state helium atom beam at thermal energy. The design focal length of the first diffraction order is 150 mm for a de Broglie wavelength of 0.18 nm. Helium beam focusing experiments have been carried out with the zone plates with 100 nm outermost zone width.