Spectroscopic phase-dispersion optical coherence tomography measurements of scattering phantoms

We demonstrate a novel technique to determine the size of Mie scatterers with high sensitivity. Our technique is based on spectral domain optical coherence tomography measurements of the phase dispersion that is induced by the scattering process. We use both Mie scattering predictions and dispersion measurements of phantoms to show that the scattering dispersion is very sensitive to small changes in the size and/or refractive index of the scatterer. We also show the light scattered from a single sphere is, in some cases, non-minimum phase. Therefore, the phase is independent of the intensity of the scattered light, and both intensity and phase must be measured directly in order to characterize more completely the scattering problem. Phase dispersion measurements may have application to distinguishing the size and refractive index of scattering particles in biological tissue samples. This manuscript describes work of the US government and is not subject to copyright.