Ultrafast optical control of excitonic structures in low-dimensional materials from first-principles calculations*

Strong light-matter interactions in layered van der Waals (vdW) materials open up a unique avenue for optical control of material properties at atomic scale. In this talk, we establish a theoretical framework to investigate the optical control of excitonic structures based on first-principles many-body perturbation theory calculations. Our work demonstrates coherent optical field as a powerful method to manipulate the excitonic properties in 2D materials. From our calculations, we find that the dark and bright excitons can be coherently coupled, resulting in novel absorption features as a function of frequency. Our work provides quantitative predictions on the change of excitonic spectra of 2D materials due to optical field, and lays the foundation for advancing optoelectronics and quantum information science.