Dr. Masoumeh Keshavarz

High Field Magnet Laboratory
Radboud University, Nijmegen, Pays-Bas

Physics of Polymers under Nanoscopic Confinement
a Single Molecule Study
I will present the direct observation of the dynamics of synthetic polymers in a confined environment
using time‐resolved wide‐field fluorescence microscopy. This work provides a complete
understanding of the characteristic dynamics of synthetic polymers in solutions in the Rouse, reptation
and diffusive regime within the single molecule approach. I will demonstrate that within one
experiment the characteristic time constants and length scales including their distributions in
heterogeneous systems can be obtained. In the second part, I will give an overview of the change of
polymer dynamics as a function of polymer concentration and intrinsic parameters of polymer chains
such as the persistence length. Moreover, I will sketch the effect of external forces such as a high
magnetic field on polymer dynamics.

Lisa Poulikakos

Optical Materials Engineering Laboratory,
ETH – Zurich, Suisse

The Optical Chirality Flux as a Useful Far-Field
Probe of Chiral Near Fields
To optimize the interaction between chiral matter and highly twisted light, quantities that can help
characterize chiral electromagnetic fields near nanostructures are needed. Here, by analogy with
Poynting’s theorem, we formulate the time-averaged conservation law of optical chirality in lossy
dispersive media and identify the optical chirality flux as an ideal far-field observable for
characterizing chiral optical near fields. Bounded by the conservation law, we show that it provides
precise information, unavailable from circular dichroism spectroscopy, on the magnitude and
handedness of highly twisted fields near nanostructures.

Contact : genet@unistra.fr