Investigating the utility of refractive index tomography based on OCT

We describe tomographic imaging of the refractive index of turbid media based on optical coherence tomography (OCT). We describe a variant OCT technique, bifocal optical coherence refractometry (BOCR), in which the optical pathlength difference between two foci simultaneously present in a medium of interest is measured. This technique is potentially suitable for dynamic measurements of the refractive index of biological tissues. We describe different schemes for realization of BOCR including one based on an adaptive liquid-crystal lens. We present experimental results from a range of tissue phantoms and from human skin in vivo that demonstrate the unique possibilities of BOCR for refractive index tomography, including its intrinsic immunity to motion artefacts and suitability for dynamic measurements