Ultrafast nanooptics

Optical mapping of the elasto-mechanical response in nanostructures (Lippitz, Sönnichsen, Vogelgesang)

Are tiny metal nanoparticles harder than bulk? How do defects and domain boundaries influence local elasticity? Mechanical properties on the nanoscale are not well understood. Until recently, the available methods dictated ensemble measurements, which necessarily provide only averaged answers. In this project, we aim at pushing the detectability limit in nanomechanics to the sub-particle level by combining ultrafast with ultramicroscopic optical techniques.

The elastic properties of individual nanoparticles are reflected in their acoustical mode spectra in the GHz to THz range. Such acoustical oscillations of the whole particle can be triggered by impulsive laser heating, leading to local shape and density oscillations. The near-instantaneous local variations of the dielectric constant thus convey mechanical information in optical scattering properties and the scattered nearfields will allow spatial resolution down to a few nanometers.

We will map acoustical modes of plasmonic nanostructures by a nonlinear optical pump-probe near field microscope. This will allow us to investigate elasticity at the nanoscale, at the limit of continuum-mechanical description. At the same time, we will learn how metallic nanostructures respond mechanically to ultrafast laser pulses, which is of great importance for nonlinear optics using plasmonic antennas and waveguides.


Nanoantenna-enhanced ultrafast nonlinear spectroscopy of a single gold nanoparticle
Thorsten Schumacher, Kai Kratzer, David Molnar, Mario Hentschel, Harald Giessen, Markus Lippitz
Nature Communications 2 (2011) 333
Real-space imaging of nanoplasmonic resonances
Ralf Vogelgesang and Alexandre Dmitriev
The Analyst 135 (2010) 1175
Plasmonic Nanowire Antennas: Experiment, Simulation, and Theory
Jens Dorfmller, Ralf Vogelgesang, Worawut Khunsin, Carsten Rockstuhl, Christoph Etrich, and Klaus Kern
Nano Letters 10 (2010) 3596
Full simulations of the apertureless scanning near field optical microscopy signal: achievable resolution and contrast
R. Esteban, R. Vogelgesang, K. Kern
Optics Express 17 (2009) 2518
Detection of Acoustic Oscillations of Single Gold Nanospheres by Time-Resolved Interferometry
Meindert A. van Dijk, Markus Lippitz, and Michel Orrit
Physical Review Letters 95 (2005) 267406
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