- Following the first successful demonstration of EUV pump / EUV probe transient grating measurements at FERMI to which our group contributed , two new important new results have been obtained and published [2,3].
- In collaboration with colleagues from Siegen and Stockholm as well as the local team at FERMI, we made the first observation of transient nanoscale gratings of magnetization, see Fig. 1 below .
- We have done the first EUV pump / EUV probe experiment in the reflection geometry and measured 50 GHz surface acoustic waves in SrTiO3 .
- Reflection mode measurements greatly expand the range of possible samples (otherwise samples must be in the form of ultrathin membranes in order to be able to transmit the EUV probe).
- In collaboration with collaegues from Paul Scherrer Institut and others, we have made the first transient grating experiment with hard x-ray excitation at SwissFEL .
. F. Bencivenga et al., “Nanoscale transient gratings excited and probed by extreme ultraviolet femtosecond pulses,” Sci. Adv. 5, eaaw5805 (2019).
 D. Ksenzov et al., “Nanoscale transient magnetization gratings created and probed by femtosecond extreme ultraviolet pulses,” Nano Lett. 21, 2905−2911 (2021).
 A. A. Maznev et al., “Generation and detection of 50 GHz surface acoustic waves by extreme ultraviolet pulses,” Appl. Phys. Lett. 119, 044102 (2021).
 J. R. Rouxel et al., “Hard X-ray transient grating spectroscopy on bismuth germinate,” Nat. Photonics 15, 499–503 (2021).
Figure. 1 Transient gratings of magnetization. (a) The concept of the experiment. The sample is kept in a homogeneous magnetization state by the external field H, which is larger than the coercive field. The two EUV pump pulses generate a nanoscale spatial modulation of the temperature, producing a transient magnetization grating in the sample. The dynamics of the magnetization grating are monitored via transient diffraction (dashed arrows) of a timedelayed probe pulse, tuned to a magnetic absorption edge. After each FEL shot, the sample is returned to the initial magnetic state by the field H. (b) Images of the transient diffraction signal collected with a CCD camera at different pump−probe delays are indicated in the individual panels. (c) EUV TG signal from a 9 nm-thick film of CoGd alloy as a function of the time delay between the pump and probe pulses recorded with and without an external magnetic field. The period of the magnetization grating is 44 nm.