Focused ion beam (FIB) milling with a 10 nm
resolution is used to directly write metallic metasurfaces
and micro-optical elements capable to create structured
light fields. Surface density of fabricated nano-features,
their edge steepness as well as ion implantation
extension around the cut line depend on the ion
beam intensity profile. The FIB beam intensity cross
section was evaluated using atomic force microscopy
(AFM) scans of milled line arrays on a thin Pt film.
Approximation of two Gaussian intensity distributions
describes the actual beam profile composed of central
high intensity part and peripheral wings. FIB fabrication
reaching aspect ratio of 10 in gold film is demonstrated.