title: Nonlinear optical imaging of single plasmonic nanoparticles with 30 nm resolution.
abstract: We show that background free nonlinear optical imaging of Au nanostructures with a resolution down to 30 nm can be achieved. To attain such performance, an ultrafast laser source (110 fs pulse duration) has been integrated into a parabolic mirror assisted scanning near-field optical microscope. Combining nonlinear hyperspectral imaging and the simultaneously obtained topography, the setup allows one to directly correlate/assign locations with nonlinear signals originating from either second harmonic generation or two-photon excitation processes. The contrast mechanisms of the far-field background free nonlinear optical image are discussed based on the different tip-sample coupling schemes and the selective excitation of the plasmonic modes.
authors: Institute of Physical and Theoretical Chemistry, Center for Light-Matter Interaction, Sensors & Analytics, University of Tuebingen, Auf der Morgenstelle 15, Tuebingen, Germany. dai.zhang@uni-tuebingen.de anke.horneber@uni-tuebingen.de.
authors: Anke
authors: A
authors: Horneber
authors: Kai
authors: K
authors: Braun
authors: Jan
authors: J
authors: Rogalski
authors: Paul
authors: P
authors: Leiderer
authors: Alfred J
authors: AJ
authors: Meixner
authors: Dai
authors: D
authors: Zhang