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.
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01 Jan 1999
TL;DR: In this article, the basic mechanisms of photo-induced space charge field formation, director axis re-orientation, and refractive index changes in fullerene C60-and dye-doped nematic liquid crystals films are presented.
Abstract: The basic mechanisms of photo-induced space charge field formation, director axis re-orientation, and refractive index changes in fullerene C60- and dye-doped nematic liquid crystals films are presented. In particular, in aligned methyl-red-doped nematic liquid crystal film, we observe a nonlinear index change coefficient as high as 10 cm 2 /W. associated with purely optically induced liquid crystal director axis re-orientation. Experimental observations of dynamic and high-resolution storage holographic grating formation, two beam coupling with gain of nearly 3000 cm -1 , optical limiting action at nanowatt cw laser power, and incoherent-coherent image conversion at μW/cm 2 light intensity level are discussed.
4 citations
TL;DR: In this article, the orientational photorefractive properties of mesogenic composites were investigated by means of two-beam coupling and degenerate four-wave mixing, and large index modulation of over 0.01 was obtained.
Abstract: The orientational photorefractive properties of photorefractive mesogenic composites have been investigated by means of two-beam coupling and degenerate four-wave mixing. Photorefractive mesogenic composites, consisting of low molar mass liquid crystals, polymer, and photoconductive sensitizer, constitute novel organic materials possessing high performance photoreractivity. The refractive index change was estimated on the basis of the theory of two-beam coupling and four-wave mixing, and large index modulation of over 0.01 was obtained.
4 citations
TL;DR: In this paper, a series of sequential phase maps from recording digital holograms is used to explore the evolution of the photorefractive (PR) effect of electrooptic crystal under various situations.
Abstract: The dynamic refractive-index-change behavior of the light-induced process in an Mn:Fe:KTN crystal illuminated by a focused light sheet can be observed experimentally by digital holographic interferometry. By numerically retrieving a series of sequential phase maps from recording digital holograms, the spatial and temporal evolution of the light-induced refractive-index-change distribution inside the material is visualized in situ and monitored in a quantitative and in full field way. With this technique, the effect of recording parameters, such as writing laser power and polarization, bias voltage, temperature, and writing time, on the Mn:Fe:KTN crystal in the photorefractive effect can be explored. Therefore, optimized recording parameters will be achieved according to the dynamic behavior. The method provides an access to explore the evolution of the photorefractive (PR) effect of electrooptic crystal under various situations.
4 citations
TL;DR: In this article, a theoretical model considering total internal reflections of fanned beams from the side crystal surfaces and their coupling with the pump beam is proposed, which results in the light intensity redistribution and in the generation of the photorefractive surface wave.
Abstract: A theoretical model considering total internal reflections of fanned beams from the side crystal surfaces and their coupling with the pump beam is proposed. The interaction of these beams results in the light intensity redistribution and in the generation of the photorefractive surface wave. An experimental observation of the light intensity self-concentration near the surface of a thin photorefractive Bi12TiO20 crystal is reported. It results in an acceleration of the photorefractive energy exchange process.
4 citations
TL;DR: The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed and in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mismatch of Bragg condition.
Abstract: The properties of anisotropic diffraction of light by volume holographic grating in birefringent photorefractive crystals are discussed. This diffraction takes place when the refractive index for diffracted light is different from the refractive index for incident light. It is found that in some special geometry of wavevector diagram the diffraction becomes less sensitive to the wavelength mismatch of Bragg condition. The wavelength range may extent in several times the range of ordinary isotropic diffraction on the grating of the same spacing and thickness. Theoretical explanation of this phenomena and experimental results of widerange diffraction in BaTiO3 photorefractive crystal are also presented.
4 citations