Measurement of the optical absorption coefficient of a liquid by use of a time-resolved photoacoustic technique

A time-resolved photoacoustic technique has been applied to the study of di ssolved and dispersed absorbers in aqueous systems. The temporal pressure p rofiles generated from colloidal graphite and glucose solutions were measur ed, and it was found that the amplitude of the photoacoustic signal of both the glucose and the colloidal graphite solutions increase linearly with co ncentration and that acoustic signal time delay yields the acoustic velocit y. The logarithm of the photoacoustic signal amplitude changes linearly wit h the time delay, with a slope that is proportional to the product of the a coustic velocity and the optical, absorption that can thus be determined. ( C) 2000 Optical Society of America OCIS codes: 300.0300, 300.6430.