New regimes of light-matter interactions are enabling exciting new science, including the discovery of “light-matter” states in quantum materials. The advent of advanced ultrafast time-domain spectroscopies based on femtosecond laser sources provides opportunities to study non-equilibrium dynamics of quantum materials in femtosecond and even attosecond time scales. This IRG will focus on i) Relaxation dynamics in 2D materials, ii) Ultrafast spin manipulation in 2D magnetic materials, and iii) Optically induced quantum phase transition in topological quantum materials.