Holographic imaging through turbid media using photorefraction

A technique, based on photorefractive holography for imaging objects obscured by a diffusing medium has been implemented in the near infrared spectral region corresponding to the absorption minimum of biological tissue. Using ultrashort pulse illumination, depth resolved whole field images of three dimensional objects embedded in such a scattering medium have been obtained. The authors have investigated the use of bulk photorefractive crystals (Rh:BaTiO/sub 3/) and photorefractive multiple quantum well (MQW) devices as the hologram recording medium. Images have been obtained through up to 16 scattering mean free paths (mfp) using bulk Rh:BaTiO/sub 3/. The fast response time (<0.4 ms) of the MQW device allows recording of depth resolved images direct to video. An image has been obtained through 13 mfp with these devices.