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
01 Jan 2007
9 citations
01 Dec 1999
TL;DR: In this paper, the conditions under which three-dimensional data bits recorded by the photorefractive effect under single-photon and twophoton excitation in these materials can be read in reflection confocal microscopy are described.
Abstract: In three-dimensional optical bit data storage, data bits can be recorded as a result of the change in refractive index in photorefractive and photochromic materials under single-photon and two-photon excitation by a high numerical-aperture objective. In principle, these recorded data bits can be read out using reflection confocal microscopy because such a microscope exhibits an optical sectioning property for three-dimensional imaging. In this article, the conditions are described under which three-dimensional data bits recorded by the photorefractive effect under single-photon and two-photon excitation in these materials can be read in reflection confocal microscopy. The effect of the refractive-index mismatch between a volume recording medium and its immersion medium on these conditions is also considered.
9 citations
TL;DR: By use of the derived formulas the diffraction efficiency for angle mismatch from the Bragg condition can easily be evaluated as compared with numerical-analysis methods.
Abstract: Formulas are given for the calculation of diffraction efficiency of reflection-type gratings recorded in a photorefractive medium. The analysis incorporates the coupled-wave theory that was developed for photorefractive hologram gratings. This analysis takes into account grating slant with respect to the medium surface, light absorption during reconstruction, any incident angle of the reference beam, and any photorefractive phase shift. General solutions for signal and reference wave functions are given in a closed-form expression by use of a hypergeometric function. The optimum media parameters and recording conditions for high diffraction efficiency are obtained by the derived formulas. The diffraction properties for off-Bragg conditions are also discussed.
8 citations
TL;DR: In this article, the dynamic behavior of the complementary space-charge gratings formed in a Bi12SiO20 crystal through prolonged recording at 780 nm is used to determine a number of significant photorefractive parameters, including effective trap density, diffusion length, and dielectric relaxation time, simultaneously for both types of charge carriers.
Abstract: The dynamic behavior of the complementary space-charge gratings formed in a Bi12SiO20 crystal through prolonged recording at 780 nm is used to determine a number of significant photorefractive parameters, including effective trap density, diffusion length, and dielectric relaxation time, simultaneously for both types of charge carriers. This simple, all-optical method does not require prior knowledge of any other photorefractive parameters and therefore represents the only procedure currently available capable of direct materials evaluation in the low-coupling regime. Furthermore, the scheme provides the means for quantitatively assessing the effects of crystal sensitization resulting, for example, from uniform preillumination.
8 citations
IBM1
TL;DR: In this article, the photorefractive properties of polymers with optically nonlinear molecules attached in a pendant side-chain configuration are investigated using degenerate four-wave mixing (FWM) as well as two-beam coupling (2BC) techniques.
Abstract: This paper describes the recent progress of our group in the field of photorefractive polymers. Three separate systems are discussed. The first two consist of polymers with optically nonlinear molecules attached in a pendant side-chain configuration, which are made photoconductive through the addition of a molecular charge-transport agent. The photorefractive properties are investigated using degenerate four-wave mixing (FWM) as well as two-beam coupling (2BC) techniques. The latter technique is essential for confirming the photorefractive origin of the FWM signals through the observation of asymmetric 2BC. The performance of various sensitizing agents used to generate mobile charges at long wavelengths is also compared for such systems. The third system consists of a charge-transporting polymer, which is made nonlinear through the addition of a optically nonlinear guest molecule. The photorefractive properties of this system are found to be superior of those of other polymeric systems, with diffraction efficiencies of 1% in a 125 micrometers thick sample for gratings written with red light (647 and 676 nm), and a 2BC gain coefficient (Gamma) which exceeds the absorption coefficient by 7.2 cm-1 at 753 nm. These properties are comparable to those of inorganic crystals, and should generate interest in organic photorefractive materials for device applications.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
8 citations