Carbazole-based photorefractive organic glass showing high diffraction efficiency at low external electric field

Photorefractive organic glass, 9-(2-ethyl-hexyl)-3-[2-(4-nitro-phenyl)-viny l]-9H-carbazole (EHCN), showing large coupling gain and high diffraction ef ficiency at low external electric field was synthesized and characterized. EHCN showed the glass transition at 25 degreesC and the good thermal stabil ity up to 400 degreesC. Photorefractivity of EHCN was investigated by using 100 i m thick films (S1, S2, S3) doped with 0%, 0.5%, and 1% 2,4,7-trinitr ofluorenone (TNF), respectively. Two-beam coupling net gain of 50.8 cm(-1) was obtained for the 0.5% TNF-doped EHCN sample (S2) at 40 V/mum field. The highest internal diffraction efficiency, obtained from the degenerate four -wave mixing at 30 V/mum field, reached 90% for the 1% TNF-doped EHCN sampl e (S3).