Nanoscale transient gratings excited and probed by extreme ultraviolet femtosecond pulses

Author
Abstract
Advances in developing ultrafast coherent sources operating at extreme ultraviolet (EUV) and x-ray wavelengths allow the extension of nonlinear optical techniques to shorter wavelengths. Here, we describe EUV transient grating spectroscopy, in which two crossed femtosecond EUV pulses produce spatially periodic nanoscale excitations in the sample and their dynamics is probed via diffraction of a third time-delayed EUV pulse. The use of radiation with wavelengths down to 13.3 nm allowed us to produce transient gratings with periods as short as 28 nm and observe thermal and coherent phonon dynamics in crystalline silicon and amorphous silicon nitride. This approach allows measurements of thermal transport on the ~10-nm scale, where the two samples show different heat transport regimes, and can be applied to study other phenomena showing nontrivial behaviors at the nanoscale, such as structural relaxations in complex liquids and ultrafast magnetic dynamics.
Year of Publication
2019
Journal
Science Advances
Volume
5
Number of Pages
eaaw5805
Date Published
2019-07
URL
https://advances.sciencemag.org/content/5/7/eaaw5805.full
DOI
10.1126/sciadv.aaw5805
JILA PI
Journal Article