Sensing polarization with variable coherence tomography

Variable coherence tomography (VCT) was recently developed by Baleine and Dogariu for the purpose of directly sensing the second-order statistical properties of a randomly scattering volume [J. Opt. Soc. Am. A 21, 1917 (2004)]. In this paper we generalize the theory of VCT to include polarized inputs and anisotropic scatterers. In general the measurement of the scattered coherency matrix or Stokes vector is not adequate to describe the scattering, as these quantities depend on the coherence state of the incident beam. However, by controlling the polarized coherence properties of the source beam, VCT can be generalized to probe the polarimetric scattering properties of objects from a single-point Stokes vector or coherency matrix measurements. With polarized VCT, we are able to design a method that can measure analogous information to the polarimetric bidirectional reflection distribution function (BRDF), but do it from monostatic data. This capability would allow the BRDF to be measured remotely without having to adjust either the incident or observation angle with respect to the target.