title: Doubling the efficiency of third harmonic generation by positioning ITO nanocrystals into the hot-spot of plasmonic gap-antennas.
abstract: We incorporate dielectric indium tin oxide nanocrystals into the hot-spot of gold nanogap-antennas and perform third harmonic spectroscopy on these hybrid nanostructure arrays. The combined system shows a 2-fold increase of the radiated third harmonic intensity when compared to bare gold antennas. In order to identify the origin of the enhanced nonlinear response we perform finite element simulations of the nanostructures, which are in excellent agreement with our measurements. We find that the third harmonic signal enhancement is mainly related to changes in the linear optical properties of the plasmonic antenna resonances when the ITO nanocrystals are incorporated. Furthermore, the dominant source of the third harmonic is found to be located in the gold volume of the plasmonic antennas.
authors.affiliation: 4th Physics Institute and Research Center SCoPE, University of Stuttgart , Pfaffenwaldring 57, 70569 Stuttgart, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Metzger
authors.forename: Mario
authors.initials: M
authors.lastname: Hentschel
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schumacher
authors.forename: Markus
authors.initials: M
authors.lastname: Lippitz
authors.forename: Xingchen
authors.initials: X
authors.lastname: Ye
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Murray
authors.forename: Bastian
authors.initials: B
authors.lastname: Knabe
authors.forename: Karsten
authors.initials: K
authors.lastname: Buse
authors.forename: Harald
authors.initials: H
authors.lastname: Giessen