New and distinct physical and chemical
properties of matter emerge on the
nanoscale
when the structure size of the material becomes comparable to the
mean-free path of the electrons or the scattering length-scale of
phonons. The research in our group is centered around the development
of
nano-optical
spectroscopies that enable both
nanometer
spatial and
femosecond
temporal resolution.
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Light scattering and scanning of a sharp metal tip
illuminated by a
focused laser source: Sample contrast and resolution are obtained by
means of the locally enhanced tip-sample interaction spatially confined
by the tip apex radius. This allows for spatially resolved probing of
the linear (ω, e.g., IR-vib), inelastic (ω
− Δ, e.g., Raman), or
nonlinear (nω,
e.g., SHG)
optical response of
the sample with nanometer spatial and femtosecond temporal resolution.
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The
optical antenna properties
of metallic nanostructures allow one to concentrate and locally enhance
optical fields to
nanometer
dimensions. This can be explored and applied for scanning probe optical
near-field microscopy with nanometer spatial
and femtosecond temporal resolution and sensitivity down to the
single molecule level. Being
compatible with a broad range of optical spectroscopies including
time-resolved
and
nonlinear
methods, we are making use of the technique for a broad range of
applications including the in
situ
study of supramolecular, biomolecular and copolymer
nanostructures, the
nanomanipulation of optical molecular
switches,
tuning the local optical coupling in molecular
plasmonics and optical antenna geometries, or probing correlation
phenmena in multiferroic or other quantum many body systems.