Photorefractive polymers for holography (original) (raw)
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Optimization of the recording scheme for fast holographic response in photorefractive polymers
Synthetic Metals, 1999
The influence of the recording scheme on the dynamic performance of a photorefractive polymer composite is investigated. In the low-T, composite studied here, the response time is at first limited by the formation of the photorefractive space-charge field and on a longer time scale by the orientation of the electrooptic chromophores. By in situ pre-poling the devices before writing the hologram a substantial speed enhancement was achieved compared with non-prepoled devices.
Polymeric photorefractive composite for holographic applications
Polymer, 2001
Applications of photorefractive polymeric composite for holographic data storage medium and phase conjugation mirror were demonstrated. Polymeric material composed of photoconducting carbazole-substituted polysiloxane matrix, 2,4,7-trinitro-9-¯uorenone, and 2-{3-[(E)-2-(dibutylamino)-1-ethenyl]-5,5-dimethyl-2-cyclohexeny liden}malononitrile chromophore exhibited a diffraction ef®ciency of 92% at an electric ®eld of 30 V/mm. Holographic recording, reading, and erasing of single page image were demonstrated using the 100 mm thick polymeric composite. We also demonstrated that the distorted phase of the object beam introduced by a image distorter was successfully restored using a phase conjugation mirror. q
Holographic multiplexing in photorefractive polymers
Optics Communications, 2000
A new multiplexing schedule is derived for multiplexing holograms in photorefractive polymers which do not exhibit mono-exponential recording behavior. An M-number (M/#) of 0.3 was measured experimentally by recording 20 holograms of roughly equal strength in a single location of 125-lm-thick material using peristrophic multiplexing. The eects of hologram dark-decay on the time-evolution of the M/# and the relative strengths of individual holograms is investigated.
Recent advances in photorefractive polymers
SPIE Proceedings, 2011
Photorefractive composites derived from conducting polymers offer the advantage of dynamically recording holograms without the need for processing of any kind. Thus, they are the material of choice for many cutting edge applications, such as updatable three-dimensional (3D) displays and 3D telepresence. Using photorefractive polymers, 3D images or holograms can be seen with the unassisted eye and are very similar to how humans see the actual environment surrounding them. Absence of a large-area and dynamically updatable holographic recording medium has prevented realization of the concept. The development of a novel nonlinear optical chromophore doped photoconductive polymer composite as the recording medium for a refreshable holographic display is discussed. Further improvements in the polymer composites could bring applications in telemedicine, advertising, updatable 3D maps and entertainment.
Visible and near infrared sensitive photorefractive polymers for holographic display applications
2007
This work presents recent advances in photorefractive polymer composites towards improved efficiency, speed, persistence of holograms and sensitivity at both visible and near infrared wavelengths. Besides the pure performance characteristics, a thin-device approach is presented to reduce operating voltage of these devices to practical levels and these materials are analyzed in both reflection and transmission geometries. The thin device operating at 1.3kV holds erasable, Bragg holograms with 80% efficiency in addition to its video-rate response time. The transition of hologram state from 'thick' to 'thin' is analyzed in detail. On the near IR portion of spectrum, new photorefractive polymer composites have been developed that enable high performance operation at 845nm and 975nm. Utilizing our novel photorefractive materials we demonstrate large diffraction efficiency in four-wave mixing experiments and video-rate response times. A major step towards achieving submillisecond response times is obtained through recording photorefractive gratings with individual nanosecond pulses at 532nm. At 4 mJ/cm2 illumination, a maximum diffraction efficiency of 56% has been obtained with a build-up time of only 300mus (t1). This fast response enables applications in optical processing requiring frame rates of 100Hz or more. Due to the short duration of the writing pulses, the recording is insensitive to vibrations. Combining molecules that have different frontier orbital energies in a copolymer system and utilizing thermal fixing approach has led to long grating lifetimes of more than several hours. Later, in this dissertation, two low-glass-transition photorefractive polymer composites are investigated in reflection geometry. 60% is diffraction efficiency is observed in 105mum thick devices of a PVK based composite. The reflection holograms are more sensitive to reading angle and slight birefringence due to the poling of chromophores has proven to cause a Bragg mismatch.
Studies on some non-conjugated and conjugated polymer systems for holographic recording
2019
Holographic 3D displays provide highly realistic images without the need for special eyewear, making them valuable tools. Current commercially available holographic 3D displays employ photopolymers that lack image updating capability, resulting in their limited use and high cost per 3D image. Photorefractive polymers are dynamic holographic materials that permit recording of highly efficient reversible holograms. The present chapter gives a brief introduction to photorefractive polymers. Mechanism of photorefractive polymers, requirement of photorefractive medium and different materials used for the fabrication of photorefractive devices are discussed in detail. Theoretical and experimental techniques used for design, fabrication and characterization of photorefractive polymers are also outlined. Discussions are also focused on conducting polymers, especially on conjugated photoconducting polymers. Moreover, the role of photosensitizers for achieving higher carrier generation effici...
Polymer Journal, 2014
A photorefractive (PR) composite based on poly(4-(diphenylamino)benzyl acrylate) (PDAA) as a host photoconductive matrix is reported. The PR performance was investigated at three different wavelengths (532, 561, 594 nm), and an optimized operating wavelength of 532 nm was obtained. The PDAA composite had high sensitivity at 532 nm with a maximum diffraction efficiency of 480%, which was achieved at an applied electric field of 40 V lm À1. An application with a hologram display system using the PR composite was demonstrated. A clear and updatable hologram of an object was successfully reconstructed in real time, even at a low applied electric field of 25 V lm À1 .
High-Performance Photorefractive Polymers
Science, 1994
Photorefractive materials can form "instant" holograms without time-consuming development steps. Their potential applications include image processing, optical data storage, and correction of image distortion, but the cost of crystal growth and preparation has been a primary ...
Dynamic holographic images using poly(N-vinylcarbazole)-based photorefractive composites
Polymer Journal, 2013
We present the optimization of poly(N-vinylcarbazole) (PVCz)-based photorefractive composite films for use in a dynamic holographic imaging system. The compositions of the composite films used in this study included PVCz/4azacycloheptylbenzylidenemalononitrile (7-DCST)/carbazoylethylpropionate (CzEPA), N-ethylcarbazole, benzyl n-butyl phthalate/ [6,6]-phenyl-C61-butyric acid methyl ester or 2,4,7-trinitro-9-fluorenone (TNF) (44/35/20/1 wt%). PVCz with molecular weights of 23 000, 100 000, 290 000, 370 000 and 810 000 g mol À1 were used. The photorefractive polymeric composite (PPC) film (PVCz with M w : 370 000/7-DCST/CzEPA/TNF, 44/35/20/1 wt%) was observed to be the most well-balanced for photorefractive performance. To demonstrate the practical application of these films, dynamic holographic images were reflected from a spatial light modulator. The optimized PPC film was used in the dynamic holographic imaging system, and well-balanced dynamic holographic images were obtained. The results from this study will contribute to the development of four-dimensional (4D À3D plus time) holographic displays.
Journal of Applied Research and Technology, 2015
In this work, we report the reversible reconstruction of holographic and distorted transmission images through the four wave mixing (FWM) technique and optical phase conjugation (OPC), an alternative method to adaptive optics, by using highly efficient Photorefractive (PR) polymers fabricated in our laboratories. These PR polymers are based on our synthesized nonlinear chromophore 4-[4-(diethylamino)-2 hydroxybenzylideneamino] benzonitrile (Dc). For the PR devices, diffraction efficiencies as high as 90% at 25 wt.% doping level of Dc at an external applied electric field (E ext) around 56 V/m are achieved. The reconstruction implementation is simple, of low cost, all-optical and it is capable of recovering 90% of the original images. The real-time holographic experiments were performed at E ext of just 27 V/m, which is one of the lowest reported values. Reversible holographic imaging is showed with a rise-time around 0.35 s.