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Thermally stable high-gain photorefractive polymers based on a trifunctional chromophore
1998 / IEEE / 1-55752-339-0
This item was taken from the IEEE Conference ' Thermally stable high-gain photorefractive polymers based on a trifunctional chromophore ' Previously, we have shown that a polymer composite based on polyvinylcarbazole, the dye 2,N,N-dihexylamino-7-dicyanomethylidenyl-3,4,5,6,10-pentahydronaphthalene (DHADC-MPN), the plasticizer N-ethylcarbazole, and the sensitizer (2,4,7-trinitro-9-fluorenylidene)malonitrile (TNFDM) had a real diffraction efficiency of 74% at 830 nm and an externally applied field of 59 V//spl mu/m. This unprecedented performance is the result of the large figure of merit of the chromophore for photorefractivity. In order to improve the thermal stability of these devices, we have developed a stable polymer composite that was prepared by mixing the dye DHADC-MPN with an inert polymer-plasticizer matrix that is more polar than PVK/ECZ. Because the dye acts as a triple-functional dopant, there is no need to incorporate a typically apolar photoconductor that would destabilize the mixture or compete with the dye for free volume. The inert polymer was a birefringence-free acrylic resin composed of poly(methylmethacrylate)-tricyclodecylmethacrylate-N-cyclohexyl maleimidebenzyl methacrylate (PMMA-TMA-CMI-BM). Diphenylisophthalate was used as plasticizer. The results are summarized.
Real Diffraction Efficiency
Large Figure Of Merit
Two-beam Coupling Gain Coefficient
High-gain Photorefractive Polymers