Novel light sources for ultrafast ultraviolet spectroscopy
Vincent Wanie (DESY, Germany)
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 presentation, I will first discuss our ongoing development of ultrafast light sources, including laser-written glass cells for generating ultrashort UV pulses via frequency conversion of Ti:sapphire lasers [1,2], and the post-compression of multi-kHz Yb lasers using multipass-cell technology for statistically demanding experiments. This approach enables the seeding of hollow-core fibers to produce spectrally tunable UV–visible pulses with few-femtosecond duration through resonant dispersive-wave emission [3]. I will then present recent studies of UV-induced electron and nuclear dynamics in molecules, highlighting photoelectron circular dichroism spectroscopy as a probe of electron-driven chiroptical responses [4]. Combined with theoretical modeling, these results open new directions for 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)
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 presentation, I will first discuss our ongoing development of ultrafast light sources, including laser-written glass cells for generating ultrashort UV pulses via frequency conversion of Ti:sapphire lasers [1,2], and the post-compression of multi-kHz Yb lasers using multipass-cell technology for statistically demanding experiments. This approach enables the seeding of hollow-core fibers to produce spectrally tunable UV–visible pulses with few-femtosecond duration through resonant dispersive-wave emission [3]. I will then present recent studies of UV-induced electron and nuclear dynamics in molecules, highlighting photoelectron circular dichroism spectroscopy as a probe of electron-driven chiroptical responses [4]. Combined with theoretical modeling, these results open new directions for 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)
