Related Experiment Video
Updated: Jul 7, 2026

Characterization of Biological Absorption Spectra Spanning the Visible to the Short-Wave Infrared
Published on: January 10, 2025
Measuring absorption coefficients in small volumes of highly scattering media: source-detector separations for which
Abstract:
The noninvasive measurement of variations in absorption that are due to changes in concentrations of biochemically relevant compounds in tissue is important in many clinical settings. One problem with such measurements is that the path length traveled by the collected light through the tissue depends on the scattering properties of the tissue. We demonstrate, using both Monte Carlo simulations and experimental measurements, that for an appropriate separation between light-delivery and light-collection fibers the path length of the collected photons does not depend on scattering parameters for the range of parameters typically found in tissue. This is important for developing rapid, noninvasive, and inexpensive methods for measuring absorption changes in tissue.
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