  An improved method of remote optical absorption spectroscopy and
hyperspectral optical absorption imaging is described which takes advantage of
the photoacoustic remote sensing detection architecture. A wide range of
photoacoustic excitation wavelengths ranging from 210 nm to 1550 nm was
provided by a nanosecond tunable source allowing access to various salient
endogenous chromophores such as DNA, hemeproteins, and lipids. Sensitivity of
the device was demonstrated by characterizing the infrared absorption spectrum
of water. Meanwhile, the efficacy of the technique was explored by recovering
cell nuclei and oxygen saturation from a live chicken embryo model and by
recovering adipocytes from freshly resected murine adipose tissue. This
represents a continued investigation into the characteristics of the
hyperspectral photoacoustic remote sensing technique which may represent an
effective means of non-destructive endogenous contrast characterization and
visualization.
