Femtosecond studies of coherent acoustic phonons in gold nanoparticles embedded in TiO2 thin films

0.15 THz coherent acoustic phonons have been observed in gold nanoparticles embedded in TiO2 thin films by virtue of femtosecond time-resolved transmissivity measurements at room temperature. The generation of these phonons is attributed to the resonant excitation of localized surface plasmon in gold nanoparticles. Their damping time is 55 ps which is acquired by fitting the oscillatory part of time-resolved transmissivity to single exponentially damped cosine function.