Pump-probe spectroscopy uses two laser pulses to extract dynamical information from the sample of interest.
The pump initiates the optical process by exciting part of the sample from the electronic ground state to an accessible electronic excited state, an exciton. The probe then interacts with the already excited sample. The change in absorbance after pumping provides information about the transitions between the excited states and their dynamics.  In this talk I will present a real-time approach to study these phenomena in solids and nanostructures. First, I will discuss some applications with a single laser source related to the nonlinear optical response, and then we will move on to pump and probe spectroscopy. The results are then analysed using a Fermi-Golden rule approach formulated in the excitonic basis set and in terms of the symmetries of the excitonic states. Using bulk LiF and 2D hBN as two prototype materials, we discuss the selection rules for transitions involving strongly bound excitons for which the hydrogen model cannot be used.

References
[1]D. Sangalli, M. D'Alessandro, C. Attaccalite, Phys. Rev. B, 107, 205203 (2023)
[2]C. Attaccalite, M. Grüning, Phys. Rev. B, 88, 235113 (2013)
[3]C. Attaccalite, M. Grüning, H. Amara, S. Latil, F. Ducastelle, Phys. Rev. B, 98, 165126 (2018) 

Coffee and pastries will be served in the hall at 11:00