Photo-acoustic determination of optical parameters of tissue-like media with reference to opto-acoustic diffraction

Tissue optical properties are determined by an interpretation of pressure transients generated by irradiation with pulsed laser light. These pressure signals are detected using piezo-electric transducers.These signals are influenced by numerous processes during generation, propagation and detection. Specific experiments were performed to study each process in particular using different substances with various absorption and scattering properties.Opto-acoustical diffraction effects cause a strong distortion of the shape of the transients. This phenomenon was investigated experimentally and verified theoretically.