Fig. 4: Schematic of a nonlinear phononic process.
From: Time-domain study of coupled collective excitations in quantum materials
a Time-dependent displacement of a resonantly-driven IR phonon excited by an ultrashort, intense laser pulse in the mid-infrared to terahertz frequencies. b The resulting force on the crystal lattice induced by the IR phonon driven to a large amplitude. c The displacement of a coupled Raman mode that results in a net structural distortion as a function of time. Adapted from ref. 47, Springer Nature Ltd.
