Title: Status and Perspective of X-ray Transient Grating Spectroscopy
When: Wednesday, 15th November, 2023, at 15:00
Where: Conference Room, Module 00, Facultad de Ciencias, Universidad Autónoma de Madrid
Speaker: Cristian Svetina, Group leader at the IMDEA Nanociencia, Madrid, Spain
Optical domain four wave-mixing techniques represent a major advance in experimental and theoretical physics, chemistry and biology. The nonlinear response of a sample under the influence of multiple laser beams allows to measure fundamental properties such as electronic response, electron-phonon coupling, propagation of wave-packets, phonons, excitons, transport phenomena and magnetic properties of the sample. Transient Grating (TG) spectroscopy is a special case of four wave-mixing employing two crossed laser beams interacting at the sample to generate an interference pattern and a third time-delayed probe beam to monitor the time evolution of the induced dynamics that transiently changes the index of refraction. TG is widely used in the optical domain to gain information on transport and diffusion processes as well as on charge-magnetic and vibrational dynamics. Extension of TG, and more generally wave-mixing, at short wavelengths would open the possibility to ultimately reach (sub)-nanometer and (sub)-femtosecond scales adding element and chemical specificity having direct access to K, L and M shells. After a brief introduction of the TG method I will describe its extension in the Extreme Ultraviolet [1] and explain the method employed to extend TG in the X-rays via Talbot effect [2] showing experimental results at X-ray Free Electron Lasers (X-FELs) [3]. I will conclude with an overview of the ongoing comunitary efforts to develop and apply X-ray TG and, more in general X-ray wave-mixing methods.
References
- F. Bencivenga et al. Nature 520, 205–208 (2015)
- C. Svetina et al. Opt. Lett. 44, 574–577 (2019)
- J. R. Rouxel et al. Nat. Photon. 15, 499–503 (2021)
- M. Chergui, M. Beye, S. Mukamel, C. Svetina and C. Masciovecchio, Nat Rev Phys 5, 578–596 (2023)
