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

Abstract

We report full-field, retroreflective holographicimaging 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 42 μ m were acquired in a few seconds using a 6.3 mW helium neon laser at 633 nm . 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).