title: 120 nm resolution and 55 nm structure size in STED-lithography.
abstract: Two-photon direct laser writing (DLW) lithography is limited in the achievable structure size as well as in structure resolution. Adding stimulated emission depletion (STED) to DLW allowed overcoming both restrictions. We now push both to new limits. Using visible light for two-photon DLW (780 nm) and STED (532 nm), we obtain lateral structure sizes of 55 nm, a Sparrow limit of around 100 nm and we present two clearly separated lines spaced only 120 nm apart. The photo-resist used in these experiments is a mixture of tri- and tetra-acrylates and 7-Diethylamino-3-thenoylcoumarin as a photo-starter which can be readily quenched via STED.
authors.affiliation: Institute of Applied Physics, Johannes Kepler University Linz, 4040 Linz, Austria.
authors.forename: Richard
authors.initials: R
authors.lastname: Wollhofen
authors.forename: Julia
authors.initials: J
authors.lastname: Katzmann
authors.forename: Calin
authors.initials: C
authors.lastname: Hrelescu
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Jacak
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Klar
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D054802:Molecular Imprinting / Q000379:methods*; D010781:Photography / Q000379:methods*; D012031:Refractometry / Q000295:instrumentation*