Holographic storage and high background imaging using photorefractive multiple quantum wells

Abstract

We report holographic, real time, depth-resolved image acquisition, storage, and reconstruction in photorefractive GaAs/AlGaAs multiple quantum wells under high background radiation conditions. Reconstructed images of 50 m transverse and depth resolution have been achieved using this device as a coherence gate to image through 9 mean free paths of turbid scattering medial © 1996 American Institute of Physics. ͓S0003-6951͑96͒04239-8͔

Direct-to-video holographic 3-D imaging using photorefractive multiple quantum well devices

“…This latest generation of MQW devices exhibited a greatly improved optical quality across their 2 mm aperture, which, together with the improved uniformity of the applied AC field, increased the field of view by 16 times compared to our previously published results [1]. Fig.…”

“…This image has been corrected for static background "noise" (which arises from light scattered from fixed inhomogeneities in the MQW device surface, the edges of the aperture and other components) by subtracting the light field recorded in the absence of a hologram. The improved optical quality and the fast (sub-ms [1]) response times of these MQW devices, however, allowed us to record useful depth-resolved images directly from the CCD camera to a conventional video cassette recorder without any background subtraction or other signal processing, such as is shown in Fig. 3(a).…”

“…[1,2]. Photorefractive multiple quantum well (MQW) devices satisfy many of the requirements needed for such recording media, such as high sensitivities [3] and very fast response times [4].…”

Optical phase conjugation for turbidity suppression in biological samples

“…Although OPC has been used in numerous laser-related applications, such as high-resolution imaging 3 , laser resonators 4,5 and pulse compression 6 , its use in suppressing turbidity in biomedical applications has remained largely unexplored. The use of interferometric wavefront sensing and holographic techniques in biomedical optics has largely focused on phase imaging and the selection of minimally scattered light for imaging [7][8][9] . We note that there have been significant investigations of phase-conjugation techniques in the microwave and ultrasound regimes.…”

High-speed wide-field coherence-gated imaging via photorefractive holography with photorefractive multiple quantum well devices

“…Holographic imaging as a means of imaging in the presence of a scattering medium was first proposed by Stetson [11] and later improved by Caulfield [12]. These techniques used photographic film as the recording medium and so real-time imaging was not possible; recent work has overcome this limitation through a variety of methods including the direct recording of holograms by a CCD [13,14] and photorefractive holography using barium titanate [15,16] and photorefractive multiple quantum well (PRQW) devices [17].…”