The Fritz Haber Institute (FHI) in Berlin is one of the oldest and highly renowned research institutes within the Max Planck Society, Germany's most successful scientific organization. At the FHI, researchers from all over the world are engaged in basic research in the fields of physics and chemistry at interfaces, catalysis research, and molecular physics. The Department of Physical Chemistry focusses on the dynamics of elementary processes in solids and at surfaces, in particular, ultrafast dynamics of electronic and lattice excitations, electron-phonon coupling, interfacial charge transfer, spin dynamics, surface reactions, as well as light-matter interaction at the nanoscale.

The Max Planck-Radboud University Center enhances the joint research capabilities of the Max Planck Society and Radboud University (Nijmegen, NL) based on their unique Free Electron Laser (FEL) instrumentation. Our state-of-the-art FELs allow for intense and nonlinear infrared (IR) spectroscopy with applications ranging from biomedicine to chemistry and materials science to astrophysics.

Within a new project of the Center, the Lattice Dynamics (LD) group in the Department of Physical Chemistry offers a

PhD Position:
Two-color infrared free-electron laser spectroscopy and microscopy

The LD group employs infrared spectroscopy and microscopy using the FHI FEL, to investigate infrared nanophotonic systems based on phonon polaritons in low symmetry crystals, as well as resonant nonlinear imaging of ferroic systems. We use complementary approaches of momentum space spectroscopy and real space spectro-microscopy to explore the unusual dispersion of deeply sub-wavelength polariton modes. For real space imaging, we have developed a novel experiment of nonlinear infrared-visible frequency mixing microscopy, providing deeply sub-diffractional infrared imaging resolution.

Topics of the research:

Within a new Center project “Two-by-two: Time-correlated and time-resolved two-color infrared free-electron laser spectroscopy and microscopy”, this PhD position will explore the unique experimental opportunities emerging from the recently commissioned two-color operation of the FHI FEL. This world-wide unique infrastructure allows to employ two independently tunable, intrinsically synchronized infrared FEL outputs for two-color time-resolved pump-probe and time-correlated frequency-mixing spectroscopies. The project aims to establish novel experimental schemes for this new mode of FEL operation, initially focusing on pulse characterization of the correlated two-color time-structure and time-resolution, as well as proof-of-concept pump-probe experiments. These experiments will make use of the LD groups expertise and infrastructure for FEL pulse structure characterization. Furthermore, the existing sum-frequency generation microscope will be extended to operate with mixing the two infrared beams with the visible in order to perform four-wave mixing microscopy with sub-diffractional imaging resolution. This third-order microscopy approach will allow investigating phonon-phonon, phonon-polariton, as well as polariton-polariton correlations, for instance in strong coupling systems.

The fully-funded PhD position is initially limited to 3 years, with a possibility for extension. The PhD student will be based at the FHI in Berlin. The willingness to spend about 20% of the time at the partner group in the Netherlands is anticipated.

Your profile:

Applicants should hold an excellent Master’s degree or equivalent in physics, chemistry, materials science or related fields. Experimental experience in one or more of these areas is highly beneficial:

Moreover, candidates are expected to have

Your application should include:

Applications for this position are only accepted via our online application portal. Closing date: Applications will be accepted until March 31, 2024. We thank all applicants for their interest. However, only those individuals selected for an interview will be contacted.

The Max-Planck-Gesellschaft endeavours to achieve gender equality and diversity. We welcome applications from all backgrounds. The Max Planck Society aims to increase the participation of women in research. Therefore, applications by women are particularly welcome. The Max Planck Society is also committed to increasing the number of individuals with disabilities in its workforce and therefore encourages applications from such qualified individuals. Furthermore, the Max Planck Society seeks to increase gender diversity in research and therefore explicitly encourages non-binary people to apply.

For more information, please contact:

Dr. Alex Paarmann
Fritz Haber Institute of the Max Planck Society, Department of Physical Chemistry, 14195 Berlin

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