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.

Photorefractive effect in GaP

Abstract: The photorefractive effect in undoped semi-insulating GaP was observed. GaP has a photorefractive sensitivity in the spectral region of 0.6 to 0.9 μm. The photorefractive center is the deep donor resulting from the P antisite defect. We measured the two-beam coupling gain coefficient and its time constant as functions of the grating period and the pumping intensity, using a 633-nm He–Ne laser. The maximum gain coefficient of 0.33 cm−1 was obtained at a grating period of 1.1 μm. The time constant, which depends on the grating period, was 3–20 msec at a pumping intensity of 30 mW/cm2.

High intensity illumination effects in LiNbO3 and KTiOPO4 waveguides

Abstract: Quasi-phase-matched waveguides are known to degrade when generating high intensity short wavelength light. Photoinduced changes in the refractive indices can lead to reduced efficiency by broadening phase-matching curves or inducing power dependent losses. In this work a pump-probe technique was used to investigate photorefractive effects in nonlinear optical waveguides. A strong two photon photorefractive effect in single domain and Ti-poled LiNbO3 was found that is considerably reduced in electric field periodically poled LiNbO3 and is absent in Rb-exchanged KTiOPO4.

Enhanced photorefractive performance in a photorefractive polymeric composite

Abstract: We characterize the photorefractive behavior of a photorefractive multicomponent polymer composite of PVK‐TCP:C60:DEANST. Efficient plasticization of the host polymeric matrix and utilization of a nonlinear chromophore with a large dipole moment provide a large poling‐induced electro‐optic coefficient. Diffraction efficiencies as high as 40% and asymmetric net two‐beam coupling gain coefficients in excess of 130 cm−1, surpassing those of known inorganic single‐crystalline photorefractive media, are reported.

Synthesis and Photorefractive Properties of Multifunctional Glasses

Abstract: A set of organic glasses has been synthesized and evaluated for photorefractive performance The functions of optical nonlinearity, birefringence, and charge transport were built into a single molecule by attaching an NLO chromophore to a charge transport moiety with an adjustable linking group The longer linking group not only lowers the glass transition temperature Tg but also influences the photorefractive performance of the samples The photorefractive gain coefficient is larger for longer linkers with about a 2-fold increase going from the 2-carbon atom linker to 12 The glass stability and chemical stability of the materials was adequate for full photorefractive characterization

Photorefractive material response to short pulse illuminations

Abstract: Photoconduction and hologram recording in a Bi 12 SiO 20 single crystal are studied from both theoretical and experimental points of view in the case of short pulse excitations. An approach taking into account two kinds of acceptor centers explains the charge transport processes in the case of both pulsed and continuous illuminations. A nanosecond temporal resolution allows us to access a time domain that is not normally considered, and on this time scale, the electron migration velocity is governed by the intrinsic mobility, which we have estimated to he greater than 3.2 cm2/V . s. Using this value, our theoretical developments explain the fast beam coupling phenomenon that we have experimentally observed.