title: Single-molecule pump-probe detection resolves ultrafast pathways in individual and coupled quantum systems.
abstract: We report the first experimental study of individual molecules with femtosecond time resolution using a novel ultrafast single-molecule pump-probe method. A wide range of relaxation times from below 100 up to 400 fs is found, revealing energy redistribution over different vibrational modes and phonon coupling to the nanoenvironment. Addressing quantum-coupled molecules we find longer decay times, pointing towards inhibited intramolecular decay due to delocalized excitation. Interestingly, each individual system shows discrete jumps in femtosecond response, reflecting sudden breakup of the coupled superradiant state.
authors.affiliation: Applied Optics Group, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217 Enschede, The Netherlands.
authors.forename: Erik M H P
authors.initials: EM
authors.lastname: van Dijk
authors.forename: Jordi
authors.initials: J
authors.lastname: Hernando
authors.forename: Juan-José
authors.initials: JJ
authors.lastname: García-López
authors.forename: Mercedes
authors.initials: M
authors.lastname: Crego-Calama
authors.forename: David N
authors.initials: DN
authors.lastname: Reinhoudt
authors.forename: Laurens
authors.initials: L
authors.lastname: Kuipers
authors.forename: María F
authors.initials: MF
authors.lastname: García-Parajó
authors.forename: Niek F
authors.initials: NF
authors.lastname: van Hulst