Ultrafast polymerization inhibition by stimulated emission depletion for three-dimensional nanolithography

Abstract

To identify the depletion mechanism in the stimulated-emission-depletion (STED) inspired photoresist composed of a ketocoumarin photoinitiator in pentaerythritol tetraacrylate, we perform lithography with pulsed excitation and tunable delayed depletion. A fast component can unambiguously be assigned to stimulated emission. Our results allow the systematical optimization of the conditions in next-generation STED direct-laser-writing optical lithography. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.