First-principles study of nonlinear optical response in nanostructured dielectric materials

First-principles time-dependent density functional theory (TDDFT) based electron dynamics calculation has been a powerful tool to describe light-matter interactions. It is widely used to describe electronic excitations and linear and nonlinear optical properties of molecules and solids. Additionally, our research focuses on innovative multiscale modeling techniques that integrate electron dynamics with Maxwell's equations to study light pulse propagation in macroscopic media.

This study investigates the nonlinear optical responses of nanostructured dielectric surfaces subjected to intense laser fields. We also analyze phenomena such as harmonic generation and the transient modifications of dielectric and absorption constants.

Our quantitive calculations reveal that harmonic generation is significantly enhanced in a periodic array of silicon cylindrical nanorods compared to a flat film surface with equivalent thickness. Besides, we have analyzed the influence of geometrical parameters, such as curvature radii, on optical efficiency. The effect of HG reflects the hotspots and resonant structures. We will also present results on the optical responses of nanograting and multilayer dielectric materials.