J. A. Viator, S. L. Jacques, S. A. Prahl, SPIE Proceedings of Laser-Tissue Interaction IX, 3254, 104-111 (1998).
A Q-switched frequency-doubled Nd-YAG laser coupled to an optical parametric oscillator generated 4.75 ns 800 nm laser pulses to create a subsurface acoustic wave in planar indocyanine green gel samples and flat segments of elastin biomaterial stained with indocyanine green. The acoustic waves traveled through the target and were detected by a piezoelectric transducer. The waveforms were converted to measurements of pressure (and temperature) as a function of depth in the material. An algorithm was developed and applied to the acoustic signals to extract information about the absorption coefficient as a function of depth in the samples.
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