Full-field coherence-gated holographic imaging through scattering media using a photorefractive polymer composite device

We report full-field, retroreflective holographic imaging through turbid media using a photorefractive polymer composite as a coherence gate. A four-wave mixing geometry was used to record and reconstruct two-dimensional images of test objects through 6.5 scattering mean-free-paths in real-time. Images with a transverse spatial resolution better than 42μm were acquired in a few seconds using a 6.3mW helium neon laser at 633nm. The photorefractive devices used are based on a poly (N-vinylcarbazole) (PVK):2,4,7-trinitro-9-fluorenone dimalenitrile (TNFDM) charge transport network, doped with the electro-optic chromophore 1-(2′-ethylhexyloxy)-2,5-dimethyl-4-(4″-nitrophenylazo)benzene (EHDNPB).