Coherent Phonons in Ag-BaO Thin Films

Coherent acoustic phonons have been observed in Ag nanoscale particles (NSPs) embedded in BaO thin film by means of the femtosecond time-resolved pump-probe technique. The oscillatory component in the signal corresponds to a very low-frequency acoustic phonon mode of Ag NSPs. The generation of coherent acoustic phonons is attributed to the resonant excitation of localized surface plasmon.