Generation and Detection of Coherent Acoustic Pulses by Femtosecond Laser Pulses

In this paper, we systematically study the generation and propagation of coherent acoustic pulses in a metal-dielectric system using a two-color femtosecond pump-probe technique at different probe angles. A long-lived acoustic oscillation is observed in a borosilicate glass coated with gold and shows different attenuation and amplitude at different probe wavelength. Our study suggests that the two-color optical pump-probe technique can be utilized as a noninvasive tool to study acoustic properties of dielectric materials.