Open AccessCharacterization of ultrafast free‐electron laser pulses using extreme‐ultraviolet transient gratings
Author(s) -
Capotondi F.,
Foglia L.,
Kiskinova M.,
Masciovecchio C.,
Mincigrucci R.,
Naumenko D.,
Pedersoli E.,
Simoncig A.,
Bencivenga F.
Publication year - 2018
Publication title -
journal of synchrotron radiation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.172
H-Index - 99
ISSN - 1600-5775
DOI - 10.1107/s1600577517015612
Subject(s) - ultrashort pulse , extreme ultraviolet , characterization (materials science) , laser , transient (computer programming) , electron , ultraviolet , materials science , ultrafast laser spectroscopy , optics , optoelectronics , free electron model , physics , computer science , nuclear physics , operating system
The characterization of the time structure of ultrafast photon pulses in the extreme‐ultraviolet (EUV) and soft X‐ray spectral ranges is of high relevance for a number of scientific applications and photon diagnostics. Such measurements can be performed following different strategies and often require large setups and rather high pulse energies. Here, high‐quality measurements carried out by exploiting the transient grating process, i.e. a third‐order non‐linear process sensitive to the time‐overlap between two crossed EUV pulses, is reported. From such measurements it is possible to obtain information on both the second‐order intensity autocorrelation function and on the coherence length of the pulses. It was found that the pulse energy density needed to carry out such measurements on solid state samples can be as low as a few mJ cm −2 . Furthermore, the possibility to control the arrival time of the crossed pulses independently might permit the development of a number of coherent spectroscopies in the EUV and soft X‐ray regime, such as, for example, photon echo and two‐dimensional spectroscopy.