Multiscale time-dependent density functional theory for a unified description of ultrafast dynamics: Pulsed light, electron, and lattice motions in crystalline solids

We have developed a multiscale computational scheme to describe coupled nonlinear dynamics of light electromagnetic field, electrons, and lattice motions in crystalline solids, where first-principles molecular dynamics based on time-dependent density-functional theory is used to describe the microscopic dynamics. The method is applicable to wide phenomena in nonlinear and ultrafast optics. To show usefulness of the method, we apply it to a pump-probe measurement of coherent phonon in diamond where a stimulated Raman wave is generated and amplified during the propagation of the probe pulse.