title: Pump-probe spectroscopy on photoinitiators for stimulated-emission-depletion optical lithography.
abstract: We report on femtosecond pump-probe experiments on two different photoinitiators in solution. These two molecules have recently appeared as attractive candidates for far-field optical lithography based on stimulated-emission-depletion (STED) inspired approaches aiming at beating Abbe's diffraction limit. For the case of 7-diethylamino-3-thenoylcoumarin (DETC), we find that stimulated emission clearly dominates over excited-state absorption, whereas the opposite holds true for the case of isopropylthioxanthone. We argue that it is desirable that stimulated emission dominates over excited-state absorption as depletion mechanism in STED photoresists. Thus, DETC is an attractive corresponding photoinitiator.
authors.affiliation: Institut fïr Physikalische Chemie, Karlsruhe Institute of Technology (KIT), D-76128 Karlsruhe, Germany. thomas.wolf@kit.edu
authors.forename: Thomas J A
authors.initials: TJ
authors.lastname: Wolf
authors.forename: Joachim
authors.initials: J
authors.lastname: Fischer
authors.forename: Martin
authors.initials: M
authors.lastname: Wegener
authors.forename: Andreas-Neil
authors.initials: AN
authors.lastname: Unterreiner