Surface Modification to Optimize Generation and Detection of Light-Induced Acoustics

Photoacoustic time-resolved pump-probe spectroscopy enables imaging and detection through optically opaque materials [1], [2]. Pump-induced acoustic pulses propagate longitudinally into a sample and are reflected from buried structures. When the reflected acoustic pulse returns to the sample surface it causes a refractive index variation which is then detected by a time-delayed probe pulse (Fig. 1a). Analysis of the probe reflectivity as a function of pump-probe delay is key to retrieving the internal structure of the sample of interest.