  We experimentally study the propagation of circularly polarized light in the
sub-diffusion regime by exploiting enhanced backscattering (EBS, also known as
coherent backscattering) of light under low spatial coherence illumination. We
demonstrate for the first time that circular polarization memory effect exists
in EBS over a large range of scatterers' sizes in this regime. We show that EBS
measurements under low spatial coherence illumination from the helicity
preserving and orthogonal helicity channels cross over as the mean free
pathlength of light in media varies, and that the cross point indicates the
transition from multiple to double scattering in EBS of light.
