Atto Fridays - Vincent Wanie

Atto Fridays Seminar Series proudly hosts:

Vincent Wanie (Deutsches Elektronen-Synchrotron (DESY), Germany)

Novel light sources for ultrafast ultraviolet spectroscopy

Continuous development in photonics and next-generation light sources keeps enabling novel spectroscopic approaches to investigate and manipulate soft and condensed matter at previously inaccessible ultrafast timescales. Laser-driven light sources that deliver vacuum ultraviolet (VUV) or ultraviolet (UV) pulses with a duration of a few femtoseconds (fs) are emerging state-of-the-art technologies for spectroscopic applications: Their characteristic photon energy and duration open up an uncharted regime for time-resolved experiments, enabling perturbative excitation - below the ionization threshold - and subsequent real-time tracking of ultrafast dynamics in neutral matter occurring over only a few fs.
In this perspective, the first part of this presentation will discuss our ongoing development of ultrafast light sources. These include laser-written glass cells for the production of ultrashort UV pulses via frequency conversion of titanium-sapphire lasers [1,2], as well as the post-compression of multi-kHz Ytterbium lasers using the multipass cell technology to facilitate statistically demanding experiments. The latter has been applied to seed hollow-core fibers and produce spectrally tunable UV-visible pulses with few fs duration via resonant dispersive wave emission [3]. Finally, I will present recent studies of UV-induced electron and nuclear dynamics in molecules utilizing the temporal resolution offered by such light sources. I will notably introduce photoelectron circular dichroism spectroscopy and how it can be used to reveal the contribution of electron dynamics to the chiroptical properties of photoexcited chiral molecules [4]. Together with our theoretical modeling, the experimental results open new perspectives for applying the concept of enantioselective, charge-driven reactivity.

[1] M. Galli et al., Optics Letters, 44, pp. 1308-1311 (2019)
[2] V. Wanie et al., Journal of Physics: Photonics, 6, 025005 (2024)
[3] L. Silletti et al., APL Photonics 10, 070801 (2025)
[4] V. Wanie et al., Nature, 630, pp. 109-115 (2024)

Please note: Part of the Q & A session has been removed at the speaker's request.

Please refer to https://www.quantumbattles.com/attofr... for the complete list of speakers and their abstracts in this seminar series.