Photoinduced processes are typically studied with transient absorption (TA) spectroscopy, which allows to unveil molecular mechanisms occurring on the femtosecond timescale1 (1 fs = 10^-15 s). Ultrafast TA spectroscopy has also been employed to follow the dynamics in molecular polaritons. This approach measures simultaneously the frequency spectrum and the temporal evolution of the interaction, allowing to observe directly the coherent light-matter hybridization (Rabi oscillations). In parallel, the most conventional method for probing the strong coupling of excitonic materials with cavities in static conditions is Fourier imaging, which measures simultaneously the frequency spectrum and angular distribution of light. In this way, one can directly observe the polariton dispersion and extract the energy of their coupling strength (Rabi splitting).
This research thesis will focus on the development of a new multidimensional ultrafast spectrometer for the simultaneous measurement of frequency, time and momentum dimensions on the ultrafast timescale, suitable for characterizing fundamental mechanisms in polaritons. The project will be performed in the context of an EU-funded project “ULYSSES”, aiming at controlling photochemical processes in real time by using ultrafast metasurfaces as a new platform for open optical “meta-cavities”. This thesis work will be performed in the ERC-granted ULYSSES laboratory.

More Info: margherita.maiuri@polimi.it
Links: https://www.ulysses-erc.eu
Vasa P. et al., Nat. Photon. 7, 2, 128-132 (2013). Maiuri M. et al., ACS Photon., under review (2024).
Russo M. et al., Adv. Opt. Mater., just accepted (2024)