Spectroscopic Microtomography in the Visible Wavelength Range

We demonstrate spectroscopic microtomography in the visible wavelength range (450-700 nm) using digital holographic tomography, a wavelength-scanning source, and a variable-optical-path-length strategy. This multidimensional imaging system can directly measure the absorption-coefficient and refractive-index spectra of a three-dimensional specimen. We apply the system developed to characterize three types of polystyrene beads (undyed, blue dyed, and red dyed) as well as oxygenated and deoxygenated single red blood cells.