FEL-induced ultrafast IR reflectivity change 2013
A FEL pulse impinging on a target interacts with its electrons, promoting in a few femtoseconds a large amount of them from their equilibrium states to higher energy bands, before thermalization and recombination bring the system back to equilibrium in a nanosecond time scale.
Danailov et al., Opt. Express 22, 12869, (2014).

Impinging with an infrared pulse with controlled delay after a FEL pump pulse allows to investigate the electron dynamics through the measurement of variations in IR reflectivity. The different behavior of several kinds of solid samples have been tested, using a 100 fs FEL pulse as a pump, followed by a 150 fs IR probe, obtained splitting the same laser pulse used to seed the FEL process. |
FEL pump and IR probe are naturally synchronized, coming from the same seed pulse: the only gitter between the two sources, due only to mechanical instability in the beam propagation setups, is estimated around 15 fs. Retrieve articleTowards jitter-free pump-probe measurements at seeded free electron laser facilities. Danailov et al. Opt. Express 22, 12869, (2014). |