Photoacoustic Subsurface Imaging

Abstract

We have performed photoacoustic imaging of subsurface in a metal using a microphone detection method. A computer controlled photoacoustic imaging system is developed. A sample in a high sensitive photoacoustic cell is scanned mechanically and photoacoustic signals generated by focused laser beam irradiation are fed into a lock-in amplifier. The magnitude of photoacoustic signal is displayed on a graphic terminal of a micro-computer which controls the imaging system. Laser power dependence of the photoacoustic signal and some examples of subsurface imaging are presented.