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Showing papers on "Organic photorefractive materials published in 2014"


Journal ArticleDOI
TL;DR: In this article, the photorefractive effect of ferroelectric liquid crystals has been studied in a wide range of devices related to diffraction optics including 3D displays, optical amplification, optical tomography, novelty filters, and phase conjugate wave generators.
Abstract: In this paper, we review recent progress of research on the photorefractive effect of ferroelectric liquid crystals. The photorefractive effect is a phenomenon that forms a dynamic hologram in a material. The interference of two laser beams in a photorefractive material establishes a refractive index grating. This phenomenon is applicable to a wide range of devices related to diffraction optics including 3D displays, optical amplification, optical tomography, novelty filters, and phase conjugate wave generators. Ferroelectric liquid crystals are considered as a candidate for practical photorefractive materials. A refractive index grating formation time of 8–10 ms and a large gain coefficient are easily obtained in photorefractive ferroelectric liquid crystals.

22 citations


Journal ArticleDOI
TL;DR: In this article, the authors reported on enhanced photorefractive response rate through control of the photoconductivity and trapping rate in organic triphenylamine-based photore-fractive materials by means of bulk state tuning.

10 citations


Journal ArticleDOI
TL;DR: In this article, the authors reported on the holographic recording on photorefractive Bi2TeO5 crystals using λ=633 nm wavelength light and found out the presence of a fast and a slow hologram, both of which exhibited rather high diffraction efficiencies.
Abstract: We report on the holographic recording on photorefractive Bi2TeO5 crystals using λ=633 nm wavelength light. We studied the behavior of this material under the action of this low photonic energy light and found out the presence of a fast and a slow hologram, both of photorefractive nature and exhibiting rather high diffraction efficiencies. The faster and the slower holograms are based on the excitation and diffusion of oppositely charged carriers (likely electrons and holes). Relevant parameters for the photoactive centers responsible for both kind of holograms were characterized using purely holographic techniques. No evidences of non-photosensitive ionic charge carriers being involved in the recording process at room temperature nor self-fixing effects were found.

7 citations


Journal ArticleDOI
TL;DR: It is shown how the competition between electron and hole conductivity can influence light propagation, leading to the self-bending effect of optical beam trajectory, which depending on the value of trap compensation coefficient may be stationary or transient.
Abstract: This article analyzes nonlinear light propagation in semiconductors with bipolar conductivity and nonlinear transport of electrons. We show how the competition between electron and hole conductivity can influence light propagation, leading to the self-bending effect of optical beam trajectory, which depending on the value of trap compensation coefficient may be stationary or transient.

6 citations


Journal ArticleDOI
TL;DR: The purpose of this paper is to find the polarizations and spatial orientations of the two interacting counterpropagating coherent light waves which ensure the largest beam coupling in monoclinic photorefractive crystal.
Abstract: The purpose of this paper is to find the polarizations and spatial orientations of the two interacting counterpropagating coherent light waves which ensure the largest beam coupling in monoclinic photorefractive crystal. The results of calculations are presented that are verified experimentally with Sn2P2S6.

4 citations


Journal ArticleDOI
TL;DR: In this paper, a polyphosphazene organic photorefractive materials with carbazole groups were synthesized by diazo-coupling reaction and the results showed that polymers had good heating stability.
Abstract: New polyphosphazene organic photorefractive materials with carbazole groups were synthesized by diazo-coupling reaction. They were characterized by 1H Nuclear magnetic resonance,infrared spectrum,Ultra-violet-visible,thermogravimetry and differential scanning calorimetry. The result showed that polymers had good heating stability. They started to decompose at 230 ℃ and decomposed completely at 450 ℃. UV-Vis indicated that the broad absorption peak ranging from 360 to 570 nm was derived from the increase in the conjugation length. Hence we can adjust the ratio of diazonium salt in the coupling reaction to control the access content of azo chromophore functional component. The photorefractive effects were investigated without electric field and polarization by two-beam coupling (2BC) and degenerated four-wave mixing(DFWM).The coupling coefficients of polymers P-2 and P-3 are measured to be about 38 cm-1 and 53.6 cm-1 respectively and the diffraction efficiencies of polymers P-2 and P-3 are measured to be about 2.7% and 8.1% respectively.

2 citations


Journal ArticleDOI
TL;DR: In this article, the measurement of grating period in photorefractive anisotropic self diffraction by using digital holography technique is proposed, and the results show grating periods, holograms and their reconstruction.
Abstract: In this paper, the measurement of grating period in photorefractive anisotropic self diffraction by using digital holography technique is proposed. In our experimental setup, He –Ne laser beam with wavelength of 632.8 nm has been separated and then incident on photorefractive cerium doped barium titanate crystal to produce photorefractive index grating. The transmitted probe beam, which contains phase and amplitude has been expanded and recorded on digital camera. To explore the grating periods, both phase and amplitude of the images are reconstructed by numerical process using computer. Then the grating periods in photorefractive anisotropic self diffraction have been measured. The results show grating periods, holograms and their reconstruction.

1 citations


Journal ArticleDOI
TL;DR: In this paper, the light-induced absorption in undoped photorefractive Bi2TeOO5 (BTeO) crystal was investigated and the so-called two-center model was shown to adequately describe the present material behavior.
Abstract: We report on the light-induced absorption in undoped photorefractive Bi2TeO5 (BTeO) crystal. The so-called “two-center” model is shown to adequately describe the present material behavior. We demonstrate that nonlinear light-induced absorption occurs for high light intensities. The theoretical model allowed us to find out some material parameters from experimental data. We also investigate the effect of intensity and wavelength on the light-induced absorption.

1 citations


Proceedings ArticleDOI
07 Oct 2014
TL;DR: In this paper, the correlation between photoconductivity and bulk state in amorphous organic photorefractive materials was investigated to probe the nature of the performance of photoconductivities and to enhance the response time and diffraction efficiency of photore-fractivity.
Abstract: For many optical semiconductor fields of study, the high photoconductivity of amorphous organic semiconductors has strongly been desired, because they make the manufacture of high-performance devices easy when controlling charge carrier transport and trapping is otherwise difficult. This study focuses on the correlation between photoconductivity and bulk state in amorphous organic photorefractive materials to probe the nature of the performance of photoconductivity and to enhance the response time and diffraction efficiency of photorefractivity. The general cooling processes of the quenching method achieved enhanced photoconductivity and a decreased filling rate for shallow traps. Therefore, sample processing, which was quenching in the present case, for photorefractive composites significantly relates to enhanced photorefractivity.

Proceedings ArticleDOI
16 Nov 2014
TL;DR: In this article, the photoelectric conversion at a non-photovoltaic photorefractive material sandwiched between transparent conductive electrodes is reported based on the light-induced Schottky effect.
Abstract: We report on the photoelectric conversion at a non-photovoltaic photorefractive material sandwiched between transparent conductive electrodes. Its behavior is based on the light-induced Schottky effect. Its nature and performance was clearly established by wavelength-resolved photoconductivity. OCIS codes: Photoconductivity (040.5150); Photorefractive Materials (160.5320); Optoelectronics (230.0250)