Revealing spin-phonon coupling by ultrafast spectroscopy in 2DMMs. (A) Time-resolved optical rotation of the probe beam detecting the spin dynamics mediated by phonon in FePS₃. Adapted with permission from [156]. Copyright©2021, American Chemical Society. (B) Amplitude of 3.2 THz phonon mode of FePS₃ by measuring transient rotation. Adapted with permission from [164]. Copyright©2022, John Wiley & Sons, Inc. (C) Phonon replica of spin-orbit-entangled exciton detected in NiPS₃ by ultrafast spectroscopy. Adapted with permission from [159]. Copyright©2022, The Author(s). (D) Ultrafast signatures of magnetophononic coupling in MnBi₂Te₄. Adapted with permission from [145]. Copyright©2022, The Author(s). (E) Coherent spin-coupled phonon dynamics in CrI₃. Adapted with permission from [161]. Copyright©2022, The Author(s).