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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TL;DR: In this article, the real-time holographic image degradation produced by mechanical stress applied to a cubic photorefractive crystal of the sillenite family was demonstrated in a diffusion only recording mechanism.
2 citations
09 Oct 1997
TL;DR: In this article, an anomalous carrier diffusion was used to write a refractive index grating in a photorefractive polymer with a D/μ value larger than that derived from Einstein's law.
Abstract: Writing a refractive index grating by anomalous carrier diffusion without applying an external electric field has been achieved in a photorefractive polymer whose D/μ value is larger than that derived from Einstein's law. A grating was written in a photorefractive polymer by anomalous diffusion.
2 citations
29 Oct 1998
TL;DR: In this article, high performance photorefractive polymer hybrid liquid crystal structures are investigated in detail by use of optical tow-wave mixing technique, where an amplification of laser light can be realized by two-beam coupling mechanism.
Abstract: The high-performance photorefractive polymer hybrid liquid crystal structures are investigated in detail by use of optical tow-wave mixing technique. In such structures an amplification of laser light can be realized by two-beam coupling mechanism. Photorefractive properties of the structures rely on the spatial light induced charge carrier density modulation in thin film of photoconducting polymer. The spatially modulated space-charge field induces efficient reorientations of molecules of adjacent to polymeric layer nematic liquid crystal forming, in this way, the refractive index grating. Efficient energy transfer between the incident and the higher-order diffracted beams has been observed in dynamic self-diffraction process on thin phase gratings at oblique light incidence. The phase shift between the light intensity pattern the light intensity pattern and the refractive index modulation grating, responsible for the energy exchange, can be controlled by the applied electric field enabling reversal of direction of energy flow. Energy transfer and diffraction efficiency are found to exhibit different response characteristics with fringe spacing, voltage, cell parameters and light modulation-depth. The net exponential gain coefficient reported for the structures amounted to (Gamma) approximately equals 2600 cm$_-1) and was obtained at driving voltages of the order of 1 V/micrometers .
2 citations
TL;DR: In this paper, the photorefractive effect (optical damage) is enhanced by the electric field applied to the waveguide, and resistance to the effect is increased when the samples are heated at temperatures as high as 80°C.
Abstract: The temperature and electric field dependences of the photorefractive effect in proton-exchanged (PE) waveguides formed on MgO-doped lithium niobate (LN) are investigated in detail for the first time. As a result, the photorefractive effect (optical damage) is found to be enhanced by the electric field applied to the waveguide. On the other hand, resistance to the photorefractive effect is markedly increased when the samples are heated at temperatures as high as 80°C. We should take these properties into consideration in designing optical devices such as electrooptic modulators and parametric devices.
2 citations
TL;DR: In this article, the photorefractive parameters of the crystal such as gain factor, Debye screening length, effective density of charge traps as well as effective electro-optic constant were measured on the basis of gain/grating spacing, gain/crystal rotation angle at different recording beam polarizations, and gain/intensity at different crystal orientations dependencies.
Abstract: Measurements are presented for the photorefractive grating recording under pulsed excitation in the crystal of CdTe doped by Fe. The crystal under study is characterized by high electron mobility in comparison with typical value.THe photorefractive parameters of the crystal such as gain factor, Debye screening length, effective density of charge traps as well as effective electro-optic constant have been measured on the basis of gain/grating spacing, gain/crystal rotation angle at different recording beam polarizations, and gain/intensity at different crystal orientations dependencies. The electron-hole competition influence on the crystal photorefractive performance is discussed. The fast photorefractive effect was shown to occur under pulsed excitation maximum gain factor, (Gamma) , being equal to approximately 0.3 cm-1 without any external electric field. Different self-action effects accompany two-beam coupling are discussed. These are two photon absorption, free carrier generation, self-action of laser beams. The photorefractive effect was separated in its pure form from the various nonlinear optical phenomena.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
2 citations