Nanoscale Transient Grating beyond Thermoelasticity - Dr. Laura Foglia (Elettra Sincrotrone Trieste S.C.p.A)

by Dr Laura Foglia (Elettra Sincrotrone Trieste)

Wednesday 22 Oct 2025, 14:00 → 15:00 Europe/Rome

aula magna

Abstract:

Collective dynamics of matter, which determine its optical, thermal and magnetic properties, often exhibit strong dependence on the length scale. Experimental tools for probing such dynamics in the sub-100 nm length-scales and on the relevant timescales (i.e. picosecond and sub-ps) mainly rely on the combination of ultrafast lasers and ad-hoc nanostructuration of the sample.

In this talk I will present an alternative approach, developed at the FERMI free electron laser (FEL), where the sensitivity to the sub-100 nm length-scale is obtained exploiting extreme ultraviolet transient gratings (EUV TGs) ¹. First, I will briefly address the applications of EUV TG to the investigation of the thermoelastic properties of materials on a previously inaccessible wavelength range ^2,3. Then, I will discuss the potential of EUV TGs in other contexts, beyond its original goal. Building upon the first demonstration of magnetization TGs ⁴, I will discuss the newest demonstrations of transient magnetization dynamics at the nanoscale ^5–7. To conclude, I will review further approaches exploiting the nanoscale periodically structured photoexcitation besides TG spectroscopy ⁸.

 

1.    Bencivenga, F. et al. Sci. Adv. 5, 257402 (2019).

2.    Foglia, L. et al. Photoacoustics 29, 100453 (2023).

3.    Bencivenga, F., Capotondi, F., Foglia, L., Mincigrucci, R. & Masciovecchio, C. Adv. Phys. X 8, (2023).

4.    Ksenzov, D. et al. Nano Lett. 21, 2905–2911 (2021).

5.    Yao, K. et al. Nano Lett. 22, 4452–4458 (2022).

6.    Steinbach, F. et al. Nano Lett. 24, 6865–6871 (2024).

7.    Miedaner, P. R. et al. Sci. Adv. 10, (2024).

8.    Foglia, L. et al. Nat. Commun. 15, 10742 (2024).

 

 

Laura Foglia started studying physics at the Università degli studi di Genova, where she obtained her bachelor degree in 2009. After graduation she moved to the Freie Universität Berlin, where she had already attended her 3^rd academic year as an Erasmus Fellow. There, she received her Physics Diploma (M. Sc.) in 2011with a thesis on “Transient reflectivity and coherent phonon generation: an ultrafast probe of the metal-to-insulator transition in VO2. From 2011 to 2015 she was a doctoral research associate in the Physical Chemistry department (Director Martin Wolf) of the Fritz Haber Institute of the Max Planck Society, under direct supervision of Prof. Julia Stähler. In the ElectronDynamiX group she developed a new approach to investigate charge relaxation and energy dissipation processes in photoexcited semiconductors and functional heterostructures: Electronic Sum Frequency Generation Spectroscopy. She received her Doctoral degree from the Technische Universität Berlin in December 2015. In 2016 she joined the experimental team of the FERMI free electron laser in Trieste and is a permanent staff scientist since 2019. Her research interests focus on time-resolved extreme ultraviolet and soft X-ray non-linear optical spectroscopies and their extension to the hard X-ray regime, in particular for the investigation of collective excitations and properties of solids at the nanoscale, including ultrafast demagnetization, magnons, thermal transport, charge and energy transfer processes.