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 paper, an atomic force microscope (AFMEM) was used for the detection of free and trapped charge carrier density, ferroelectric domains and the topography of the sample.
Abstract: Electrostatic force detection with an atomic force microscope (AFM) is ideally suited for the study of the surface properties of dielectric materials. The AFM allows simultaneous detection of many physical quantities like free and trapped charge carrier density, ferroelectric domains and, of course, the topography of the sample. Usually, photorefractive materials are optically investigated: volume refractive index gratings are observed by light diffraction. In contrast, the AFM offers the possibility of directly observing the physical steps for the development of a photorefractive grating. Due to the high sensitivity and the unprecedented lateral resolution, the AFM provides a wealth of new possibilities for the investigation of photorefractive materials. We present results obtained with Sr0.61Ba0.39Nb2O6 (SBN) crystals. The samples had as-grown as well as polished surfaces. Spatial distribution and temporal dynamics of photorefractive charge patterns are successfully resolved. Furthermore, additional cha...
3 citations
TL;DR: In this article, the effect of a trapping molecule on two closely related monolithic organic photorefractive (PR) materials was described, and it was found that the trapping molecule C affects the PR performances differently in two materials made from either A or B, although the two molecules have similar chemical structures.
Abstract: A peculiar effect of a trapping molecule on two closely related monolithic organic photorefractive (PR) materials was described. It was found that the trapping molecule C affects the PR performances differently in two materials made from either A or B, although the two molecules have similar chemical structures. Detailed studies on the charge mobility with the time-of-flight technique and activation energies for charge transport revealed that the trapping molecule C plays the role of electron trapper in material A and bipolar trapping center for both hole and electron in material B.
3 citations
TL;DR: In this paper, temperature dependence of the photorefractive effect in proton-exchanged waveguides formed on a lithium tantalate crystal is investigated, and it is shown that resistance to the effect is improved when the samples are heated at temperatures as high as 80° C.
Abstract: Temperature dependence of the photorefractive effect in proton-exchanged waveguides formed on lithium tantalate crystal is investigated. The index change induced by the photorefraction is reduced by the annealing process. Resistance to the photorefractive effect is greatly improved when the samples are heated at temperatures as high as 80° C. In the low-intensity region, the dark conductivity seems to be dominant in the photorefractive effect.
3 citations
TL;DR: In this paper, a nonlinear optical active tricyanopyrroline-based plasticizer was also synthesized and introduced into the prepared molecular glass so as to control the glass transi-tion temperature of the photorefractive matrix.
Abstract: The authors report the near-IR sensitive star-shaped molecule [D-(CBz-TCP)3] containing bifunctional chromophores. A nonlinear optical active tricyanopyrroline-based plasticizer was also synthesized and introduced into the prepared molecular glass so as to control the glass transi-tion temperature of the photorefractive matrix. In a doped glass, they observed significantly enhanced photorefractive performances with regard to the asymmetric energy transfer and the diffraction efficiency at 830nm. In the presence of a small amount of (2,4,7-trinitro-9- fluorenylidene)malononitrile, they could demonstrate a very large net two beam coupling gain higher than 300cm−1 and a diffraction efficiency of 58%.
3 citations
IBM1
TL;DR: In this article, a new class of photorefractive polymers is described in which an inert polymer binder is doped with a great molecule called a dual-function dopant, which has the dual functions of providing optical nonlinearity as well as charge transport as required for the photore-fractive effect.
Abstract: A new class of photorefractive polymers is described in which an inert polymer binder is doped with a great molecule called a dual-function dopant, which has the dual functions of providing optical nonlinearity as well as charge transport as required for the photorefractive effect. These materials are the first photorefractive polymers to show both nondestructive readout as sufficiently low reading power and optical trap activation, in which pre-irradiation by a uniform light beam increases the concentration of deep trapping sites in the material. In the area of potential applications, a new sample configuration is described in which photorefractive polymers are fabricated into an electric field switchable stratified volume holographic structure. Individual layers may be activated by applied electric field leading to improved diffraction efficiency and angular selectivity.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
3 citations