Electroabsorption and orientationally enhanced electroabsorption grating in an azo-dye-doped photorefractive composite

摘要

We report a strong electroabsorptive effect in a photorefractive polymeric composite of 1-n-butoxyl-2,5-dimethyl-4-(4'-nitrophenylazo)benzene:poly(N-vinylcarbazole):2,4,7-trinitro-9-fluorenone with a weight ratio of 44:55:1. An electroabsorption coefficient as large as 27 cm~(-1) at 632.8 nm was measured with an applied field of 92.4 V/#mu#m and an incident angle of 60 deg in air. This effect was found to depend strongly on the incident angle of the beam. With the quick translating technique, an orientationally enhanced electroabsorption grating was observed in the composite. Contributions to the electroabsorption grating were proved to be approx 1/3 from the variation of the magnitude and 2/3 from the variation of the direction of the total electric field inside the sample film.