Higher-order acoustic phonon oscillations in Au nanoparticles controlled by a sequence of ultrashort strain pulses generated by superdiffusive hot electrons

One of the quests in ultrafast plasmonics is the development of devices, based on surface plasmons and operating at high frequency and negligible heating conditions. Towards this goal, the authors use ultrashort strain pulses, generated by superdiffusive hot electrons to excite high-order spheroidal modes of Au nanoparticles. Their vibrations are accessed via periodic shifts of the surface plasmon band and further coherently controlled by a sequence of strain pulses. These results open new perspectives for ultrafast acoustoplasmonics towards the terahertz frequency regime.