Maxwell+TDDFT multiscale simulation for optical response of nanomaterials

We have been developing a novel multiscale simulation method which combines the time-dependent density functional theory (TDDFT)-based first principles electron dynamics and finite-difference-time-domain (FDTD)-based electromagnetic calculations. We apply this method to light propagation / scattering problem by semiconducting silicon nanoparticles and nanodimer structures with the length scale at a few hundred nanometer, which are often used as building block of optical devices. Under an irradiation of an intense femtosecond laser pulse (I > 10¹⁰ W/cm²), carrier excitations by multiphoton processes take place due to the enhanced light field at the focalspot / hotspot. Thus, this method offers a useful tool to analyze optical nonlinearity at nanostructures in the first principles level.