  In this article we characterize optoacoustic signals generated from layered
tissue phantoms via short laser pulses by experimental and numerical means. In
particular, we consider the case where scattering is effectively negligible and
the absorbed energy density follows Beer-Lambert's law, i.e. is characterized
by an exponential decay within the layers and discontinuities at interfaces. We
complement experiments on samples with multiple layers, where the material
properties are known a priori, with numerical calculations for a pointlike
detector, tailored to suit our experimental setup. Experimentally, we
characterize the acoustic signal observed by a piezoelectric detector in the
acoustic far-field in backward mode and we discuss the implication of acoustic
diffraction on our measurements. We further attempt an inversion of an OA
signal in the far-field approximation.
