Photoacoustic method for the simultaneous acquisition of optical and ultrasonic spectra

A novel method for the simultaneous acquisition of optical absorption and ultrasonic attenuation spectra is described. The technique is based on the photoacoustic generation of bi-directional ultrasonic pulses by a thin optical absorber that is remote from the sample. A single piezoelectric transducer ultimately detects the two pulses of ultrasound, and the captured signals are used to determine both the optical absorption and ultrasonic attenuation properties of the sample. Measurements on a polycarbonate resin sample using the simultaneous photoacoustic method and conventional techniques show good agreement, indicating the validity of the method.