Topic
Organic photorefractive materials
About: Organic photorefractive materials is a research topic. Over the lifetime, 697 publications have been published within this topic receiving 13041 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: The investigation of the light-induced changes of refractive index in a LiNbO(3): Fe sample in case of strip-like illumination shows that character of the dependences of the refractiveIndex on the coordinate perpendicular to the illuminated strip is different for different strip orientation.
Abstract: The investigation of the light-induced changes of refractive index in a LiNbO3: Fe sample in case of strip-like illumination is presented in the contribution. The changes of the refractive index are visualized by interferograms of the sample obtained for various orientation of the illuminated strip and various polarization of the light used during interferogram creation. The investigation shows that character of the dependences of the refractive index on the coordinate perpendicular to the illuminated strip is different for different strip orientation. It indicates the possibility that for different orientation of gradient of the illumination the different mechanisms are responsible for changes of the refractive index.
13 citations
TL;DR: In this paper, the complex coupling constant of a photorefractive polymer was measured as a function of an applied electric field by use of a modified ac phase modulation technique, and the accuracy of the photore-fractive phase shift as measured by this phase-modulation technique was ± 1° near phase shifts of 90° and ± 3° near phases shifts of 45°.
Abstract: The complex coupling constant of a photorefractive polymer was measured as a function of an applied electric field by use of a modified ac phase modulation technique. We determined that both a photorefractive index grating and a nonphotorefractive absorption grating were present. The electric field dependencies of the amplitude and the phase of the photorefractive gain coefficient were accurately described by standard photorefractive theory. The accuracy of the photorefractive phase shift as measured by this phase-modulation technique was ±1° near phase shifts of 90° and ±3° near phase shifts of 45°.
13 citations
TL;DR: In this article, the photorefractive effects of pure and iron doped KNbO3 crystals with concentrations between 150 ppm and 300 ppm were investigated and the experimental results were discussed in terms of a two carrier model.
Abstract: Photorefractive effects of pure and iron doped KNbO3 crystals with concentrations between 150 ppm and 300 ppm have been investigated. In order to optimize the photorefractive recording times and the amplitude of the refractive index changes the crystals were thermally treated with simultaneous photorefractive testing. The photoconductivity data and the photorefractive beam coupling gain dependent on the grating spacing show that the relative influence of electron and hole contribution is altered depending on the reduction treatment. The experimental results are discussed in terms of a two carrier model.
13 citations
TL;DR: A photorefractive system is a system which is simultaneously photoconductive and electrooptic as mentioned in this paper, and it can be produced by the photogeneration, drift or diffusion and subsequent trapping of mobile charges.
Abstract: A photorefractive system is one which is simultaneously photoconductive and electrooptic. Diffraction gratings or holograms can be produced in a photorefractive material by the photogeneration, drift or diffusion and subsequent trapping of mobile charges. The grating is produced by the internal space charge field set-up by these charges which, via the electrooptic effect, produces an index of refraction grating. Until 1990 all photorefractive systems were inorganic crystals such as LiNbO,, BaTiO,, B,,SiO,, InP:Fe, GaAs, or multiple quantum well materials. In 1990, the first observation of the photorefractive effect in an organic material, a carefully grown, doped molecular crystal was described. This was followed in short time by the discovery of photorefractive polymers. The early photorefractive systems, polymeric and crystalline, were inefficient compared to inorganic systems but in recent years the efficiency and sensitivity of photorefractive polymers have become equal to inorganic crystals. This paper describes the origins of the photorefractive effect and the design, synthesis and characterization of photorefractive polymers. In addition an orientational enhancement of the photorefractive diffraction efficiency is discussed. This orientational enhancement does not occur in crystalline systems, since it relies on the ability of the optically nonlinear chromophores to be aligned not only by an externally applied field, but also by the sinusoidally varying space charge field produced during photorefractive grating formation.
13 citations
TL;DR: In this paper, the photorefractive properties of YAlO3 crystals under 488-nm and 632.8-nm illumination were investigated and the kinetics and efficiency of holographic recording on the light grating period were obtained.
Abstract: Mn-doped YAlO3 crystals were investigated for photorefractive properties under 488-nm and 632.8-nm illumination. Dependences of the kinetics and efficiency of holographic recording on the light grating period were obtained.
13 citations