Affiliation:
1. Helmholtz Institute Jena
2. GSI Helmholtzzentrum für Schwerionenforschung GmbH
3. Universität Hamburg, Institut für Experimentalphysik
4. Class 5 Photonics
Abstract
Ultrashort ultraviolet (UV) pulses are pivotal for resolving ultrafast
electron dynamics. However, their efficient generation is strongly
impeded by material dispersion and two-photon absorption, in
particular, if pulse durations around a few tens of femtoseconds or
below are targeted. Here, we present a new (to our knowledge) approach
to ultrashort UV pulse generation: using the fourth-harmonic
generation output of a commercial ytterbium laser system delivering
220 fs UV pulses, we implement a multi-pass cell (MPC)
providing 5.6 µJ pulses at 256 nm, compressed to
30.5 fs. Our results set a short-wavelength record for MPC
post-compression while offering attractive options to navigate the
trade-off between upconversion efficiency and acceptance bandwidth for
UV pulse production.