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Pulsed photoacoustic signal characterization incorporating near- and far-field diffraction effects
Author(s)
Dewhurst, R. J.
Date Issued
January 1, 2005
Type
Article
Abstract
For the interpretation of photoacoustic waveforms, a diffraction correction method is presented based on an exact Lommel diffraction formulation. It is already known that tissue optical absorption coefficients may be determined by using a time resolved analysis. Normally, corresponding experiments measure signals close (a few mm) to a photoacoustic source. However, it is sometimes desirable to perform signal detection at distances extending towards the far field. Changes in pulse shape occur as a photoacoustic wave propagates into the far field, due to diffraction effects from the finite source/detector geometry. The paper presents a new method to recover initial photoacoustic signal profiles. Photoacoustic pressure signals in the frequency range of 100 kHz to 12.5 MHz were considered in this paper. Experimental evidence validates results predicted for the case of a 1.0 mm hydrophone. © 2005 IOP Publishing Ltd.
Citation
Measurement Science and Technology, 16(4), 885-899, 2005