title: High-resolution Fresnel zone plate fabrication by achromatic spatial frequency multiplication with extreme ultraviolet radiation.
abstract: We used an approach based on the self-imaging property of gratings to fabricate high-resolution Fresnel zone plates (FZPs). Under certain conditions, the illumination of a parent ZP with a wideband EUV beam produces a radially oscillating intensity distribution with double the spatial frequency of the ZP. This intensity distribution is observed in a certain distance range, given by the local zone width, the focal length of the ZP, and the spectral bandwidth of the illuminating beam. This phenomenon has been used to lithographically record daughter ZPs that have approximately half the zone width, thus twice the resolution, of the parent ZP. FZPs with zone widths as low as 30 nm have been fabricated in this way. Use of this technique in the extreme ultraviolet (EUV) region has the potential for high throughput production of FZPs and similar high-resolution diffraction optics with variable spatial frequency for the EUV and x-ray regions.
authors: Laboratory for Micro- and Nanotechnology, Paul Scherrer Institut, CH 5232 Villigen-PSI, Switzerland.
authors: Sankha Subhra
authors: SS
authors: Sarkar
authors: Harun H
authors: HH
authors: Solak
authors: Menouer
authors: M
authors: Saidani
authors: Christian
authors: C
authors: David
authors: J Friso
authors: JF
authors: van der Veen