An investigation was made of a photoacoustic technique for determining the optical absorption coefficient in solids. A train of laser pulses was passed through the solid, and a piezoelectric transducer attached directly to the sample measured the amplitude of the elastic wave generated by the absorbed radiation. Calibration was performed at a wavelength of known absorption. The sensitivity of the technique was found to be limited to about 1 × 10-5 cm-1 in our samples due to radiation scattered onto the transducer, but the technique is capable of measuring absorption coefficients in the 10-6-cm-1 range using laser powers of about 1 W.
A. Hordvik and H. Schlossberg, "Photoacoustic technique for determining optical absorption coefficients in solids," Appl. Opt. 16, 101-107 (1977)