Abstract
Time evolution of thermal expansion in the crystal lattice of diamond was studied on the time scale from 100 ps to 18 s upon heating of the crystal through the entire thickness by a penetrating optical laser pulse of 8 ps in duration. Bragg reflectivity curves were measured at different instants of time using pump-probe high-energy-resolution x-ray diffraction with strain sensitivity. The observed time-dependent variation of Bragg reflectivity was found to be in agreement with dynamical diffraction calculations for a crystal with propagating strain generated by thermally induced stress. The strain propagated at the speed of sound for longitudinal waves from both crystal surfaces into the bulk.
- Received 10 April 2012
DOI:https://doi.org/10.1103/PhysRevB.86.054301
©2012 American Physical Society